We have had no issues since implementing their product two years ago now! It has been wonderful working alongside them as they are always ready answer questions quickly & professionally (which isn't easy around here!), especially when I've gone off my game at some point during our monthly training calls which happens regularly :) They're also one-stop shop - everything you need if it relates directly or indirectly back into shopping cart products/services from multiple providers e.g., payment gateway partners etc...
Nothing really so far!! Just wish that we could do away wtih shipping fees by using another provider but there's not much else about this app itself apart then price compared against other options out there too..