I earned mileage with them 2 or 3 times. The tracking system was rudimentary (I often had to fax in receipts), and I had to call them to redeem miles (which came via snail mail in form of paper certificates). But their staff are very friendly and helpful.
They used to commonly have lower rates for a given hotel than the hotels' own sites, Expedia, etc. Lately that hasn't been the case, so I have basically stopped using them.