It seems whatever complaints you could possibly have for the first one has been addressed in ME2. Inventory management is more streamlined and most importantly the gameplay has been overhauled. It is more action packed and story is still as intriguing as ME1. The ability to import your save file from the previous game provides a more personalised gameplay as all the decisions made in the first game get carried over and you can truly see it's benefits (or misfortune).

Ps. That final mission makes this game the best RPG I've ever played