My son (11) and I play Supreme Commander a lot, particularly in network mode both in cooperation and competition. This set has both the original Supreme Commander game and the new add-on Forged Alliance. As mentioned above the graphics in Supreme Commander are a bit bland as mostly you are zoomed out in low-res map mode, with your units as just flags. However in the Forged Alliance add-on, the graphics get a boot up in quality and you do see far better droid detail and explosion graphics ... unless you are zoomed out and all the units are flags again. Terrain detail looks a bit more interesting in a Luna landscape sort of way (different to Supreme Commander at least). The game menu and control layout has changed a lot, but all the old commands are in there somewhere.
We have NVidia 7950 and 8800 GT graphics, 3-4Gb RAM PCs with fast motherboards and both games do stutter occasionally with the older 7950 card (thats no gaming slouch), but Forged Alliance still looks great. This won't happen on older DirectX 8 graphic cards or integrated 915 Intel graphic chips though as the games will refuse to install anyway. The battle plans and armies are pretty much as the older Supreme Commander and you get a 'new' alien (The Seraphim - the guys wiped out earlier in SC and the inspiration of the classy Human Aeons, followers of The Way). Apparently the Seraphim also occupied other worlds in the Quantum Realm, as you do, and the extermination of their cousins by Human UEF forces has made remainder of the Seraphim frumpy. The Seraphim are only available for control in skirmish and network play (you need another Forged Alliance CD to find that out). You get a few new weapons, e.g. Tech 2 missiles, as well. My son loves the add-on but 'they do attack quite fast even on easy' i.e. it's harder to play than SC, although you can set a time limit before they are allowed to attack. There are loads of patches on-line, so ensure they are all applied in order. Network play is as fun as before, and different enough to justify buying the 2nd Forged Alliance CD, although building major units seems even more agonisingly slow and so often we chose original Supreme Commander for network battles. My son and I are enjoying the Forged Alliance campaign mode, where the Seraphim only seem to be available as the rather crazed enemy. The Seraphim seem to have a very human approach to weapons production though (i.e. their units are as samey as the three humanoid factions), e.g. they have an ACU, a Tech 3 Siege Tank, a Tech 2 air cruiser, a Tech 2 Vishala air transport, an experimental nuke carrying Ahwassa bomber (OK that's a bit new) etc...
I bought this double pack despite having Supreme Commander, as it was going for the same price as the Forged Alliance add-on only, so why not get another Supreme Commander game CD free, giving a spare for a second PC or a Mate (and if you haven't got Supreme Commander it's even better value). Since patching the games seem to crash rarely if ever, - although the gameplay does stutter very badly when zooming in on a really busy area. Unlike my son I don't go for SIMS games like Rome Total War and Settlers IV, I'm more a DOOM3, QUAKE4, Thief III guy, but I find Supreme Commander very compulsive and have been through all the campaigns already. For me (and my son) around £15 for the double pack from Amazon was a steal and I would highly recommend it.