I stopped trying to play Crisis Core after Cloud showed up. The whole "sneaking to avoid the guards thing while having to keep up my body temperature" thing made me wanna throw my PSP somewhere.
As for Dissidia, I dunno but my main motivation is to play with my brothers so I got hooked leveling Ultimecia and Zidane to 100 and getting them good equips... but that's mostly it though. Story wise, it was stupid.
VERY stupid.
I won't go into the whole "VIII sucks, IX sucked the most, VII was mediocre" argument... Heaven knows VII has fond childhood memories for me which is why I'm biased towards it...