I played HG for quite a while before patching and modding and after and I can safely say the game is poor, but still somewhat enjoyable. Before patching it suffers from horrible camera glitches and other bugs but none quite as annoying and stomach turning as the whole grenade problem. The AI will rather throw a grenade than anything else with deadly accuracy. I never had as many reloads as with this game, it literally was load, dead load dead, load, dead etc. Even in 1v1 situations the AI will throw a grenade at your feet, sometimes at incredible distances. You got poor graphics, horrible voice acting and literally dead gameworld to boot. Albeit it being quite big and there are 4 or so paths you can take, it still seems quite empty. Its funny how every map seems to have 1 lootable box among 50 and NPCs if talkable, wouldnt really be of much interest or depth.
The patch seems to solve some of these problems, the camera is no longer a problem, they claim to have fixed the grenades, which is a lie and the game doesn't crash anymore. To make it more playable I suggest a couple of mods on top of the patch
Hired Guns Reinforced Adds a good number of weapons, using skins that were made by the developers but never used, as wells as gun attachements and other things
http://www.matrixgames.com/forums/tm.asp?m=1986518
DJ's Grenades Mod It fixes the grenades problem for good.
http://www.matrixgames.com/forums/tm.asp?m=1983497
DJ's Shop Mod Gives you all the weapons from the start and changes starting funds, you can also only use one of these options.
http://www.matrixgames.com/forums/tm.asp?m=1974752
I suggest you poke around the forum and read the hints and tips section too, this game is not very easy.
If I was asked why I played the game if its so horrible the answer is simple. I got bored of JA2 after playing it a zillion times with various mods. There is just so much I can play a game.