WOW I've never heard of festool and hilti but simple googling has turned up amazing stores of their customer service. Unfortunately it looks like they don't overlap completely in the types of tools Ryobi offers.

I really like Ryobi's 18V and 40V 'ecosystem'. Every time I am browsing Home Depot or their website, I come across new items that are compatible with these two ecosystems.

Just recently I saw everything from 18V Ryobi Glue Gun to a Portable Power washer that can suck water from a bucket (eliminating the need for a hose) to even a portable soldering iron! Hell they even got a boombox ha ha!

For the 40V I saw cool things such as a portable power generator, lawn mowers, wet dry vac and even a portable refrigerator.

Its really cool that there are like a bazillion things that your existing batteries can plug into.