Used Coopers Residential to rent a small flat a while ago, and they were very professional and helped arrange viewings at good times late in the evening as I work late, and they were always there waiting for me when I turned up for viewings. No problems on the deposit and the search agency was very quick in their checks.
Any issues (only minor) were dealt with quickly with the landlord, and good communication to ensure all were happy.
Again, on moving out they arranged the inventory clerk to go round to ensure the place was clean and I had my deposit returned promptly having shown them my final bills being paid. I would recommend these to any prospective tenant and landlord.