Just used a company. charges 3x with no guarantee. expensive and risky but gets good prices (£8-£10 fronts) and £12 minimum full houses.
had the usual crap drop offs, messers, one offs, non payers etc, left with about 300 of ongoing work i reckon but only had it done last week so no way to tell yet.
worth it? i think so long term, if you can afford to wait for a return