I'll start with this, I prefer Command & Conquer: Red Alert 2 to this one but it's still a really great game that everyone should give a try.
The soundtrack is awesome, for once, the allies aren't the primary faction or at least In my opinion, the Russians are.
The Japanese are really nice to use but I'd like if there could be at least 2 more factions.
The game can be pretty challenging against hardest AI though, unlike Generals Zero Hour which is easy In my opinion, but it's not as a challenging as Command & Conquer 3 which In my opinion is the hardest, of course, I'm talking of the hardest difficulty in game.
1. Command & Conquer: Generals Zero Hour
2. Command & Conquer 3: Tiberium Wars and Kane's Wrath
3. Command & Conquer: Red Alert series
first and second are kind of equal to me, they both got their flaws and their qualities, I love both at the same level, they both have great campaigns and a great story but totally different, I must admit that I prefer the one of Command & Conquer 3 but at the same time I prefer the units in General Zero Hour, depends, sometimes I could say I prefer one and the other time I would say the opposite, both are really great.
That's my favorite list (between them because there are others of course).
I'd suggest this game to any science fiction and real time strategy games.
If you like the Japanese a lot and/or play with one character only (Japanese campaign), I'd suggest you get Red Alert 3: Uprising which is a expansion (standalone) that is pretty great too.
I'd suggest you try every Command & Conquer except Command & Conquer: Tiberium Alliances which is a mmo and it is really bad, about Command & Conquer 4, you should give it a try for free before buying it.
There is also Command & Conquer: Renegade which is a fps, great game, it was one of my favorite when I was younger.
Anyway, to get back to this game, It is not the best Command & Conquer ever but it is one great strategy game.