Okay, let's keep this short: the sequel, Phantom Renaissance, is a much better game, and it's got my actual review explaining why the series is basically the best turn-based strategy/tactics games I've ever played. Compared to this game, it has all the same mechanics, better graphics, and more units. The only reason to buy this one is for the singleplayer missions, and it's got a LOT of them. So either:
1. You already have Phantom Renaissance, in which case all I have to say is that this one has as many missions, and they're just as good. The AI is a little worse, and falls for cheap tactics much more frequently, but it's really not a bother.
2: You don't have any Massive Assault game, and you're wondering if the Massive Assault Collection is worth it. In which case... that actually depends on if you have a friend(s) who likes turn-based strategy/tactic games and might want the Collection too. Yup. You see, neither this game nor its sequel have multiplayer capabilities, while Network is nothing but. So if you just want to play singleplayer, you're better off getting Phantom Renaissance now and then deciding whether to get the 'extra mission DLC' once you've beaten it, because it'll only cost you €2. If you're also interested in multiplayer... while there's quite a lot of players still playing Network 2 (their site says 185 right now), you're really gonna want a friend if you want to play regularly. And if you do, you're better off getting the Collection even if you don't want this game in particular.
...Right, was that clear enough? Basically, don't even consider
this game's existence until you've played Phantom Renaissance.
In any case, I still love the hell out of extra missions, so this is definitely a recommendation for me!