I have an Aqueon 2.5 for my betta. It's working great. I decided against using a filter in mine so I do a 50% water change once a week and then a total water change along with gravel cleaning once a week. I don't use a siphon for mine. I just stick a long wooden spoon in the gravel and stir it up to get the debris floating and then I use a cup to get the water out. It's not perfect but it seems to be working.
I like the Aqueon because it's an attractive tank and it comes with the filter (if you want to use it) and a lighted hood. Here's a picture of my tank.