excellant letter on recent rash of coil leaks with R 410a at this link Coil Corrosion
I for one have great hesitation on installing any R 410a system until this is honestly explained and resolved in a believable way by all manufactures. This is my primary concern and worry that I too will be hit with $500-$1000 repair bills even with warranty covering parts and I would have no heat or AC for days or weeks with a R 410a leak. Tin plated U bends, e coated coils , forget it, has not helped. Find the real cause and a real long term solid solution or No Sale.