The Q deal you ran into is a bargain, so I would jump on it, and sell it if you don't like it as you can surely make your money back and possibly a little profit.
The Tamron 70-300 on the Q leaves a little to be desired, mainly because the purple fringe that lens produces gets amplified, and also because the best results with that lens are stopped down to Q diffraction territory.
Good fast primes work best adapted on the Q, but as others have noted the usability is not for handheld sports action telephotos, more like tripod/static wildlife shooting .
Like I said, at the price you found you won't lose anything if you decide it is not for you. Be warned though, it is an addictive little camera