It is obvious that even with powerfull computers full convultion takes a lot of processing power. Line 6 have used convultion, but we don't know in what way, and what is power of DSP in POD. Judging by CPU consumption of their software that depends on CPU (in toneport and guitarport) it seems that it is not using much more of processing power than some of the more demanding VST plugs. So maybe they have used tricks here and there to reduce CPU consumption and sacrified a bit of quality. Do they really have a single impulse for every box or it is just a few of them, modified with EQ? Do they use full convultion, or just partially, as it is also possible (waves reverb uses this technique for reverb, only part of the impulse can be used to reduce processing power.). Then it comes to commercial choices: What is sound we think people will like the most when testing POD in store? (That may not be sound that works best for recording) What micing technique we have used etc. Kazrog impulse may work better not because he does anything more advanced than Line 6 but because he has very narrow and focused idea of sound he likes, sound that a lot of people here like. Etc.