whichever one fits.
my experience should be worth little:
Last year I had K2's T1 DB (Double Boa) and it was a giant turd for me. My feet hurt all year.
This year I have Tm-Two's and they happen to fit...great! Also they have traditional laces and make me wonder wtf I was doing with those knobs on my boots and what am I missing out on now...? (nothing except skinning as Killclimbz pointed out to me
Also had a BOA lace fail, getting a replacement was no issue but the whole mechanism was fouled when I tried to replace a simple cable, which just left me completely fucked and so happy to burn them and get a pair that fit.