/bangs head on table. :mad:

Out of a powergaming PoV, yes, as Imprisonment does not require any other means (spells, melee) to be lethal. Time Stop is more powerful only if:

(1) Target is immune to Imprisonment, but not Time Stop (not very likely, although some improved enemies have this habbit of raising SI: Abjuration).
(2) Target has some unique Phat Lewt we're interested in (also, not very likely in most cases).

I'll ignore that retarded "but you need to get closer!" argument, as one has to be retarded himself if his spellcaster is interrupted by melee hits. ;)

To conclude - yes, in a given common-scenario-X, Imprisonment is probably stronger than Time Stop. It's not as fun, though.

I'll disagree on the grounds that Imprisonment means using a 9th-level spell to kill only ONE enemy. :D True, you (probably) need to use other spells to provide the killing power to support your Time Stop, but that's what Time Stop is all about--the light show at the end!