I don't know why, but to me they are just the prettiest tail type. Halfmoons are pretty and all, but I can't stand to see fish weighed down with such heavy fins. I really like halfmoon plakats, too. I want one badly. lol. What's YOUR favorite tail type and color? I like red Betta the best. They are gorgeous and really pop against the green of the plants.
i've fallen hard for HMPKs. they're beautiful, and don't have all that finnage to shred. don't get me wrong, i've fallen for some VTs, but they're just so common, and it's hard to find them in interesting colors anymore. :< i adore my CT, but their rays curl so easily. x-X and, with HMs and Deltas, you get tailbiting alot more than with VTs. :< i adore females more than males, too. x3 sshh! don't tell my boys.
for colors, i'm fond of white, white with blue, and dalmatians. <3
I don't really have a favorite tail type. The only betta I've had is a delta tail, but since he's a chronic tail biter he always has a raggedy short tail instead. I think I'll always be more inclined to choose based on the color pattern without really caring about the tail type, though. To be honest, I'm not particularly fond of the doubletail look, but if I saw one that had a really nice color pattern, I would still consider buying it.
Edit: As far as colors, I really like my betta Ivan's color, kind of a metallic blue. I also like red, dark gray (not sure what that's officially called), copper, and multicolors.
I Love VT's! They have a lot of energy and personality (I've heard many people say VT's tend to have more personality than HM's) And the ones around here a beautiful color-wise. They're all beauties, and they can come in just as many colors and color patterns as HM's it's just a bit rare.
Vt's are full of spunk and energy in a big tank compared with most fancy Bettas. Unfortunatly people are mislead and when they see the sad motionless VT Bettas in cups and the more energetic HM's in cups... well, which do you think they'd choose? People don't realize that VT's have one amazing personality once put in a large tank, it'll go off like a big colorful firework.