I can't speak to those two since I haven't personally use them, but there's a large cost to switching platforms because the one you were using was discontinued or they jacked up the prices to unreasonable levels.

Software rarely does everything you want it to. It'll do 80%, maybe 90% if it's good, but there's always missing features and options. With open source code, businesses can have someone add those features, change things, and fix bugs. With closed source software, the best you can do is report it to the vendor and wait.

The common theme here is that you are not in control of things that are vital to running your business. That is a risk. How big of a risk depends on how big of a business you have and how big the software/service provider is. Even if they are responsive now doesn't mean that will always be the case.