I'm cautiously optimistic. The merging and/or cross-listing of inventory sounds like it could create expanded choice.
However, it could work in the opposite direction as they carry fewer long-tail items. It already happened with Lesrentals acquisition of ATS Rentals. They used to be my go-to for a wide variety of projectors at reasonable prices but all of that inventory was dropped when they were bought. Bummer.
Price-wise I think they have been fair. We'll see if the merger reduces the instances of promos which, to date, have been pretty freely available.