I love the look of the evolve. I would say bigger is better because well your going to have a couple inches from the top anyway unless you plan on getting a cover or something to deter from jumping. :)
Have you seen the fluval flora and Fluval ebi? They are about 8 gallons, have an awesome background. With tax they'd be a bit over $100.
The flora comes with lots of live plant stuff, the ebi comes with some shrimp stuff, like food. I'd go for the flora unless you want to raise shrimp. Posted via Mobile Device
I've never had a betta jump, or even my goldfish. In the evolve photos, they really fill their tanks.. I usually leave about 1" to 1 1/2" of air.
If you keep them long enough, you will. My goldfish don't jump as they are fancies and too heavy to propel themselves very far, but I have had two betta wind up on the floor and two jump a divider. Betta are jumpers.