EPIC spell experiences

i thought i'd start a thread where players could post their experiences using the epic spell system. since there's so little info about this, and i've noticed a few people have posted w/questions on the forum [me included], i'm hoping this will grow into a sort of repository where players can go to find out the nitty-gritty on epic spells.

so please post your experiences here so that others will have some guidance as to how they might want to pick their spells.

seed: conceal
variant: improved invisibility
i like this one a lot. note, however, that it does not perform as you'd expect; that is, it's not like an extended version of the standard 'improved invisibility' spell.
- first of all, i don't think there's any concealment. the pre-epic spell grants 50% concealment.
- secondly, you stay invisible even when you're in combat. that's right -- you could be thrashing a beholder on one end of the ... erhm... 'room'? ... and the other ones in the room won't even notice you there! and you stay that way a full 12 hours [gametime] long! the pre-epic version cancels invisibility once you enter combat, but maintains 50% concealment.
all in all, i like this variant. i think it adds interesting variety to the game and i've found it a useful addition.

seed: summon
variant: celestial CR20
this one, on the other hand, is one to avoid. you end up w/a celestial paladin deva that hangs around for a grand total of 1 minute 43 seconds realtime. however, the short amount of time for the completion of the duration of the spell will most likely never be arrived at because w/an AB of only 22, only 140 hp, and AC 16 ...your little deva is going to be dragonfood in the first round of combat anyway. i feel like my 16,000 xp and 450,000 gold would've been better spent elsewhere.

seed: slay
variant: 1 creature 650hp max
unfortunately i can't test this one due to a bug in the system. i'm looking forward to the bugfix so i can test the mettle of a little mayhem-sowing madness.

seed: vitality
variant: full heal hp + cure poison + cure disease
well, i haven't been poisoned or diseased yet, but the full heal works as advertised, and it's definitely pretty useful.