Looking at getting a Trane heat pump to replace an existing A/C unit. Heard some comments that the Spine Fin coil design Trane uses is difficult to keep clean and can actually clog up if not cleaned properly. I've heard good things about Trane overall but wanted to know if this design creates any long-term maintenance / efficiency issues.

That coil style has been around for over 40 years. It has worked well during that time. The new style foam cleaners work well to clean that coil. NOTE always back wash from the inside out to clean.