This review is from my personal experience with the game and completing it to 100% as well as all of the 4 schools at 100% and it might resonate with what other people think as well. Please note this is an experience that i've had while playing with a keyboard and a mouse and the controls I've mentioned and personally used might be different compared to what other people use as their controls. I could talk more about it but i forgot some of the points i wanted to mention. I have left the comments on for my review, just in case this blows up.

1. I was initially pushed off from buying the game when it came on sale, considering its history wasn't so great. However, i heard a lot of the issues were fixed, so i bought the game anyways. At the moment of writing this GTA The Trilogy means you are buying three remastered games - GTA San Andreas, GTA Vice City and GTA III. When i actually started playing the game myself, i could instantly tell the game was originally made to be used with controllers as the camera controls simply sucked. Nothing that an easy search on the internet can't fix though. Now the camera was as controllable as in the original game. Apart from one crash with Unreal Engine, i had no issues at all. The graphics were simply amazing but it was the fact that i was able to play a retro game in 60 FPS that amazed me. Overall, it feels like i'm playing the original game, i personally didn't even notice that i was playing the remastered version while doing some certain missions and i'm not sure if this is a good thing or not. I mean, this is supposed to be feeling like the original game and currently, at the moment of writing this review it's doing that job decently, with just some problems.
2. What surprised me was the fact that you are now able to retry the mission from the last point you were instead of having to completely restart it which was the case in the original game is amazing and it quite ironically gave me the confidence i needed to have to use the retry mission feature as few times as possible. What i also liked is the autosprint on the bike, you no longer have to spam the W button to make CJ ride the bike faster but i believe this should've been a feature to be toggled from the settings as this means you cannot ride the bike normally as in the original game either. The Forklift, the Dozer and the Tow Truck are all easier to use, as instead of having to press the numpads, you can simply press a button and it will for example lower the bar or raise it easily. Which i also think should've been a toggleable feature because you cannot freely control it anymore unlike the original game. Maybe you wanted to do cool things, i don't know. What is completely annoying to me are the hydraulics, you can only adjust them and not play with them anymore, you basically can't do the nice dances while going with the car like you could do in the original game. I hope this gets fixed.
3. The graphical issues still seem to be hiding in some places of the game. To be completely honest, i didn't really notice them apart from when i was in some certain areas in Las Venturas (particularly in the sand near the motorway) and while going with a Mountain Bike on Mount Chiliad. The textures on Chiliad compared to the collisions are so distanced that you can even hide CJ in some certain places. This isn't bothering me much, but it's still an issue. Do you care about Marco Forelli? You likely don't, so didn't the developers because he's that one character that was completely forgotten. His textures are still from the original game, but you won't notice that as you kill him from a distance anyways, unless you use a sniper rifle and you zoom in or you really go near him to have a chat, remember he isn't friendly at all. In some parts there are still blades of grass floating, but it's not as bad as it was before. A funny glitch worth mentioning that appears only in the Definitive Edition and not in the original game is a random NPC that does nothing but spawns in the middle of the road near to where the San Fierro gym is. Whenever i went near there i always made sure i'd kill that NPC, for me it stopped spawning when i was finished with the completion of the three export lists so.. maybe it is related to it? Speaking of glitches, it seemed like my export list was already progressed with one car, meaning when i came to the third and last list and i exported what it seemed like the 9th vehicle from the third list, i got the mission passed song, achievement and i have had 30 out of 30 cars exported even though on the board it still showed i had the Journey left to export. Despite me thinking this will affect my game progress, i got 100% completion, so this didn't prevent me from completing the game at all. While doing the boat school, the last test awarded me a 4-star wanted level and police after me while doing the test. Still, i managed to do it just fine. Now i am not sure if this is the case in the original game as well because i always did the boat/bike schools only after i finished the plane school. I guess i wasn't supposed to do the boat school while still being in San Fierro. Another visual glitch that isn't that fun is when flying a plane, if it is a little bit damaged and you hide the landing gear then one wheel will still show up and/or flicker.
4. The new attention to detail is a pro as well. For example, the snapshots have permanent purple shadows that are visible on the ground regardless of if you have and use a camera or not. Some may find this useful, especially if you forgot to photograph a snapshot and it's the last one you have. In the original game, you were left with only the snapshot itself - you wouldn't know what snapshot you missed unless you manually checked each snapshot location with the camera. Now of course you can use something like GTASNP and see exactly where's your missing snapshot/gang tag/horseshoe/oyster is but maybe you don't want to do that. During the End of the Line i specifically liked how shooting Big Smoke in his armor with a Minigun did absolutely nothing. As far as i remember, this wasn't the case in the original game and it just shows the purpose of wearing armor more clearly. If any bug that was useful was fixed, it seems like you can't do C-Bug anymore. Left-clicking while holding a gun will now also let you aim it and not just shoot it in a straight line, which is also a great change in my opinion. Sometimes you have to get creative, because some turfs are so small that no enemies will spawn in and you will have to lure the enemies from another territory just to kill them while in that turf to start a gangwar, which i don't remember being the thing in the original game, but either i have played it too long ago that i completely forgot how gangwars work or i have never actually bothered taking all of the gang turfs. But maybe they should fix more bugs, which leads me to point number 5.
5. The controls. Unlike the original game, you are more limited in terms of what you can make the keyboard keys do. As a result, you are going to find the flying controls a hell. I managed to fly a plane just fine but that's because i adjusted my controls to work with a plane, a boat and a normal vehicle. After over 1000 hours in the original game in multiple years of gameplay, i would always forget that there are completely different controls for piloting a helicopter. You'll see what i mean when you try flying the Hydra, since it has both a hover mode and a jet mode. If there's anything i hope gets fixed, it's this. We need better controls for the helicopters. It was a pain flying the helicopters, especially in the air races. Those for me were nothing but pure pain and torture. Still, with pain comes greatness and since i wanted to get 100%, i kept trying and did them anyways.

Is this worth it? Well, yes, it still feels like the original game for the most part. I recommend you wait until a sale comes, which is what i did.