SEV is okay, it's certainly not much to look at though. Especially compared to GC2. And the multiplayer in it is kind of a moot point, considering you can only do tactical combat in singleplayer. The latest patches supposedly fixed most of those glaring bugs it had at release. I still prefer GC2 over SEV, though.
But about Masters of Orion 2... I still keep two very old computers (AMD K5s, if you remember those) for the exclusive reason of playing MOO2 with some friends of mine. That game is over 10 years old, and *still* no one has made a multiplayer 4x space game that even compares to it. It had multiplayer, it had TACTICAL multiplayer combat (turn based as well), it had ship design, customized races, you name it. The game is still very popular on some gaming web-rings, there's still a Kali league for it with lots of active players. There's even an 'unofficial' patch made by some very devoted fans that fixes/tweaks a few things. It's not a mod; this guy actually somehow reverse-engineered the exe. I have no clue how he fixed one of the well-known crash bugs without the source code...
http://www.lordbrazen.blogspot.com/2005/01/download.html
A lot of games have come very close to achieving what Moo2 set the standard for, but none have surpassed it. And frankly, none have even used the same design scheme. We get these 4x space strategy games that are either real-time, or they're turn based but with autocalced battles, or they're missing multiplayer, or both.
Why can't anyone take the proven Moo2 game model, and run with it?
I mean, half the fun of designing your own ships is actually *using* them in a game of chess-type tactical turn based combat.
Anyway, if you're interested in it, good luck finding a copy. Sometimes I'll see copies of Moo2 on eBay. Just remember that game is extremely old, and is optimized for DOS. Playing it in Windows is not recommended.