Alright, I've gotten this tank too. It's super cute and I love the way it looks-- I previously had a 2.5 but it was a dinged up critter-keeper type, and this looks much nicer.
Fist thing-- I didn't pile the gravel up to the filter and it too my fish all of about 2 mins to get curious and wedge himself behind the filer. The filter is strong, however my male is a PK and does not seem too troubled by it unless he is swimming at surface level directly in front of it. I may baffle it anyway, but he's not being thrown around in there or anything. I 100% would not put a long-finned male in this tank without baffling it though.
It is as you said very roomy-- the design is quite appealing imo. I'm really glad this review was up, cause I got this tank and I'm loving it already. I'll get pics once the air bubbles vanish some. :P