DMC5 > DMC4> DMC3 > DMC1 > DMC2 > DmC

DmC's probably is better than the first three games' engines objectively, but I never liked Unreal 3. It's just unappealing with its constant pop in, bad load times, and how other than Mortal Kombat 9 it seemed like every console game using that engine ran like garbage. I also just generally don't care for how Unreal 3's lighting and texture resolution looked in a lot of games personally.

The PS2 games I can't speak too much on honestly. They run well for the time at a smooth 60 fps, generally load fast, and look good for the time they released in, especially 1 and 3.

MT Framework in DMC4 was overpowered. That thing was a beast on 7th gen, as it powered a few of Capcom's games including MvC3, RE6, and even Dragon's Dogma. Aside from the last one mentioned, all those games run really well on their original consoles, and they all look really good. The early HD era was a pretty rough time technically for a lot of devs, so for MT Framework in DMC4 to be as polished as it was in 2008 is damn impressive. It later went on to be used in some games even later into the 8th gen with Monster Hunter World and MegaMan 11 too, not bad for an engine that old.

Finally 5 has the RE Engine, and I've just always had a soft spot for this one. It really does mostly come down to how it's the best optimized for most platforms, the games all being nearly 100% in engine all the time, and the fact that I think every game I've played that uses it I like, whether it's DMC5 or one of the many RE games to use it. I was a bit worried it might be a bit too dour visually when it was rumored DMCV (before DMC5 got announced properly) was going to use it, but that was based solely on REVII which to be fair was a very dingy horror game set in a corrupted swamp home. I think it's safe to say after games like RE3R and Monster Hunter Rise it can definitely power a wide variety of aesthtics.