Yep, for $7 more I'd go for the 2.5 Minibow! I have 3 and all of the Bettas in them love em muchly. ^^

For the Whisper filters, you can fashion a "current killer" to it by simply cutting off the flat middle portion of a plastic soda bottle. Just fix the plastic around the lip of the filter, where the water pours out, and it'll almost completely kill the current.