OK, so looks is where you are going to lose on subs, lol.. They are all ugly, I have seen very few attractive ones, my wharfedales are really nice looking, curved cabinets and digital displays, with real veneer, and Funk makes some curved cabinet good looking subs, but with 99% of the ID companies you are getting a square box, and veneer and piano is going to cost a premium and sound the same...
So with that being said, with you list I pick the vtf15 and if you can go with the wood vs the black and it fits your room, go for it... its a good looking sub...
Another thing to keep in mind is dual subs sound better, so in most cases 2-$500 subs will sound better and be louder than 1-$1000 sub....
So for sound quality I would go with dual vtf2's over the 15, I actually did, lol...