I have no experience with SH3, but my SH5 game time is increasing all the time. Visually I think its the best of the range, and as said above there are somethings it cannot do. Myself I think the sinking mechanics are a let down, but again that's my personal opinion.
I think you should at least try it and with the Mods that are available you should be able to taylor the game to something that you enjoy.
If it wasn't for the hard work of the modders of this community the game wouldn't be where it is now and for that I say thanks
