Pros:
+ Ragdolls
+ Clear water makes spotting Ichtyosaurs easier
+ 16:9 resolution support
+ Actual 3D skybox on the cliff level

Cons:
- High-res impact decals and blood splatters clash with low-res surface textures
- New lighting effects don't look nice with low-poly models and old textures
- Better physics engine is largely unnecessary
- Isn't much of an improvement on the original GoldSrc version
- Contains nearly two decades worth of unpatched bugs

Conclusion: Just get the original, it looks and plays much better.

Pros: + Ragdolls + Clear water makes spotting Ichtyosaurs easier + 16:9 resolution support + Actual 3D skybox on the cliff level Cons: - High-res impact decals and blood splatters clash with low-res surface textures - New lighting effects don't look nice with low-poly models and old textures - Better physics engine is largely unnecessary - Isn't much of an improvement on the original GoldSrc version - Contains nearly two decades worth of unpatched bugs Conclusion: Just get the original, it looks and plays much better.