There are plenty of sales/ finance companies out there to be careful of. Getting comparable quotes for the same size and brands is key.
Also ask them if they complete the installations in house.
This is a huge part of the quality control of solar systems.
Companies that sell the system and install it will always produce higher quality work.
Because YOU are the customer and not the sales company giving them the install.
This includes making sure you get the correct training in how to use your system.