Scenario Campaign is garbage, but it's an easy way to get money n' parts, plus if you like loot games, it kinda works in that way to get rare items.
The PSP version is pretty good. Installed, the load times are around 5 seconds...about the same as the console versions. They dropped the 3D characters on the select/versus screen in favor of artwork, but the quality of the portraits is so UGLY...grainy as hell. Really nice port; at times it's really impressive (almost, if not all the background details are there, like the jet flying right over you on the fallen colony stage, falling through floors, etc. etc.), but at other times it looks like Tekken 5 DR PSP (I could swear Lili's character model is the same). Like Soul Calibur Broken Destiny, there are no replays. They also changed it so that characters intro and win poses have no background music, although it's kind of hard to hear some characters on the console versions, so I don't mind this. For whatever reason, there's also no 3P outfits for any of the characters that got them. Customization is also limited, although a large amount of stuff is still there.
One thing I have read but cannot confirm for myself yet is that when playing ad-hoc versus, you are limited to only four stages. Can't say I'm bothered by this either, since I got this game strictly for practice on the go. But that is weird since DR and Soul Calibur let you play on any stage.