Yeah its a good amp, only quarrels being its massive and the power connections are only capable of accepting 4 gauge at max. Even with the summer heat though and with it pumping the subs hard I havent had any issues of it cutting out due to getting too hot.
Yes the chaos is a really good sub. At the moment ascendant audio and fi audio subs are the most sought after by the SPL enthusiasts on talk audio.
The guy who designed the ascendant audio subs is also the same guy who designes the Fi subs and he also designed the RE Audio subwoofers. He no longer works for RE Audio however as they were bought out and went on to form Fi Audio and Ascendant audio. Personally I would say getting the Chaos would be a worthwhile investment over the vibe sub. The chaos would run lovely off 1200rms daily. Most people who have the same subs as me run theirs double the rated RMS power (1200rms a sub, instead of my 600rms a sub) and they say it performs much better.Tthe guy who designed them seems to make them pretty much indestructible as long as the amp isnt sending out a clipped signal due to the gain settings being to high and the sub distorting.
Also nothing wrong with second hand subs, wouldnt buy from ebay though unless the item was listed by a person off a respectable forum. You can find 2nd hand bargains on the
www.talkaudio.co.uk classifieds. Well worth having a look there. Done quite a bit of selling and buying myself on there.