I actually got my io26 for $300

To be honest, though, I'm on my third unit. I exchanged it for a new one twice at Guitar Center. The first one kept causing clicks and pops in my speakers. Looking back, this may have been caused by my wireless adapter at the time, maybe the buffer. I'm not sure. It could have been defective, just don't know. Either way, I exchanged it for another, which didn't have the clicking problem, but for headphone 1 jack the left channel was messed up. This one was definitely defective. So I exchanged it again and didn't have either of those issues again
My experience was pretty atypical though. I haven't read about anything similar, and I asked the guy at GC if anyone else had been exchanging their io26 and he said no.
Heh, $300/400 to $700 is a big jump. However, here's a Presonus FP10, which looks to basically be the same as the io26, but with no ADAT In like you mentioned (
http://www.musiciansfriend.com/product/PreSonus-FP10-10x10-FireWire-Interface?sku=242036) and it's $400.
I always see people recommending Firepods, and I always feel so strange being the only one to chime in and recommend something different (the io26).