"Rent a roof" was always going to have issues as regards the lease implications, long term. I've never dealt with them-all my clients are buying outright; it's the logical option.
If, and it's a big if, the install was done properly; then, on an owned system, it seems to have had a positive impact on the house price- the problems are all going to arise from the teams of guys who were ramming in 2 or 3 4kw systems per day. The install works; but technically won't meet mcs standards- not that they care, it's another scam-type self certified thing.
Any good installers will do roof- and wind- load assessments before anything else- again, it's back to the quality of the installer.