Even without True Shot (which is broken in both the disk and download version), rangers are very effective (especially using Poison Weapon). See, for example, Archery as a warrior - my thoughts
Do you want widescreen or higher resolution support? IMO that is the primary factor to consider for disk vs download version. In the disk version Finnigan (Verdistis inn cellar) is a decent trader and you can complete his quest and then buy back his unbreakable lockpicks; in the download version he doesn't have much of an inventory, and you can not buy back the lockpicks (so it is better to not complete the quest). The download version is slightly more buggy, but issues are still moderately rare (I played the original unpatched disk version for half the game and didn't run into any serious problems; the minor issue I did have is fixed in the download version, and was fixed at the time by a hotfix). Many issues, if encountered, have fixes or workarounds.
This may help with Win 7, as well: Windows 8 slow graphics problem fixed using WineD3D
In the Steam discussion Game Too Fast
someone reported that limiting the FPS helped. Depending on the source of your stuttering, a FPS cap might help. Might be worth trying, anyway.FPS Limiter Universal: Stabilize the performance of your games