I'm fairly new to Reaper but I like it so far. It's mostly aimed at recording not live performance, but it acts well as VST host and you can jam with it. I love snapping tools. I found it very easy to work with but I have to try Ableton I got with my interface.
Ah I see. But even for recording (which I did almost none of, expect some nifty inter-application recording, especially getting MIDI data out to Chrome and sound back into FL to record web synthesizers through Jack Audio) I find FL Studio to be so simple, literally arm and record, in 3 clicks.
My uncle's band uses Reaper for recording their lives, and that's where I got to play with it quickly, but they didn't have huge amounts of VSTs to play with.