Built in 8" sub means nothing... it just means the vantage design struggles to reproduce mid-bass so it needs a traditional driver to do handle that aspect. Although 34hz extension is nice, you're still missing nearly an octave of sound, not to mention subsonics You will still need a true dedicated 12" or 15" subwoofer for real bass. I recommend two Rythmik FV25s.
Anyways I would get the Vantages personally. What is the impedance graph on them?