I grew up playing turn based squad level games like X-com and the orignal Jagged Alliance. Saying that I have enjoyed Jagged Alliance 2 is an understatement, I purchased my first copy when it first came out back in 1999, the add-on to it Unfinished Business was okay but didnt have the same replayability as JA2. The different personalities of the hirable and recruitable mercenaries can be annoying due to their inability to get along sometimes, but can also be quite amusing; years later I was still finding interactions with voice overs that were brand new to me.
The game is great in it's initial offering but the real fun comes from all of the modifications you can find for free online. The best one out there was made by the JA2 community and is called version 1.13 (1.12 was the last update released by the OEM), it increases the resolution and adds several modifyable dynamics to the game including mobile militia and hundreds of real world weapons, ammo types, gear, ruck sacks, assault packs, etc. I have had this game for 12 years and find myself getting bored of it enough to put it in a drawer somewhere only to dig it out a few month later and spend another 50+ hours playing it from start to finish.
The comparison to Silent Storm in the other review doesnt do JA2 justice; Silent Storm was enjoyable but it had that typical rough-edged, forcefully changed from Russian to English effect that seems to hover over all current games of the same type, including the latest Jagged Alliance: Back in Action that seems to try to dumb down a lot of the action as well. Sure, JA2 was difficult, but that was because it required you to think. Throughout the game you will have to manage resources including funds, equipment, and personnel while constantly facing a numerically and techknowlogically superior adversary; You have to adjust your tactics constantly in order to overcome these issues. Once you begin to progress through the story you will find the lopsided-ness of each tactical encounter begin to diminish until you are finally able to send it some top-tier operators with excellent weapons, virtually unstopable... well, at least until you find what is waiting on the outskirts of Meduna. Hint: Bring something big;)