Maybe I should have put a bit more info in that post with those links. You want to know real world thoughts on some of these tanks, I didn't really offer that.
The Tom... I believe it is made of acrylic and if I am not mistaken, even the flat sides have a slight curve to them. This makes viewing the fish a bit "off" as the curvature of the acrylic magnifies your view. The filter may be a bit too strong for a Betta at 80 gph.
Marineland, I have owned several of their small tanks like that one. None of them stuck around for long. The acrylic scratches and I had one even get small micro cracks along the bottom. Filtration is usually good in Marineland products but they do require the constant purchase of new filter pads and if it has a bio wheel it may make some noise.
Tetra Crescent... it just looks cheap to me. I don't like the filters either. Those things take up a lot of room and you will have to buy Tetra refill filters for it.
For around $50 you can get good quality if you know what to look for, and do exactly what you are doing, ask.
Take the Penn Plax Radius for example ( I just bought the 3.4 gallon), it is made of glass, has curved front edges, completely rimless and makes for a very nice display. Very modern and expensive looking.... as far as the tank that is. The filter is nothing to jump for joy about but it is sufficient for a betta. The light is a bit lack luster but I can recommend a few really nice upgrades for the light varying from $10 to $60+, depending on if you are planning serious plant growth or not.
This is my Radius. It's new, has a few upgrades and I'm still working on plant growth.
That is the 3.4 gallon.
You said 3 gallons max, so you could look at the Vertex.
Same style tank, 2.7 gallons. It just needs a light.
You can get clip on LED lights for anywhere between $20 to $60 that would make that little tank pop.
There are also some really cool looking LED stick lights on Ebay that can even go in the tank starting out around $10.
Another good option would be the Fluval Spec or Aqueon Evolve. Both available in 2 gallons (Evolve comes in a 4 gallon as well)
Spec: all glass construction, huge filtration system, all in one (yet simple) design.
I have one of these as well. Great little tank. The filter is huge and very effective. The LED light is good for some low light plants. It looks nice, it's unique, does NOT look cheap. I am even thinking about buying a second one.
This is what mine looked like when Dante was in it.
Now it's at my home with a new betta in it and it's growing some new plants.
I'm thinking about getting another to go on the other side of the Edge.
The Evolve: These are new to the market. They are acrylic, but not that thin cheap acrylic like you see on the Eclipse systems, these things are thick, high quality acrylic. Same idea as the Speck, filter is in the back, led light on the top (yes, they do have a cover), however... the filter design isn't as good as the Speck. They use a standard drop in disposable filter pad so you will be buying filters for it unless you mod it in some way. They don't have any good bio media but it's easy to add your own.
the Chi... glass, unique, (5 gallons but it's a tall 5 gallons so the base is kind of small). The filter is ok for a betta, it's not big nor powerful but it has a gentle flow. The tank is glass, good quality and it's very stylish.
They do make a lid now so you can add that and not worry about your fish jumping out.
All in all, I think the Vertex with a nice light would make you happy.