In my experience, Reaper seems to be a favorite of a lot of mastering engineers these days. I don't know any producers/mixers who use it to craft songs. I haven't looked deep enough to say why that is. As I understand it, Reaper is generally full featured and competent with no loss of any fidelity. I think it's flexibility of audio routing and excellent conversion algorithms may be a reason so many mastering engineers turn to it.

Where it's going to differ (and you could say lack) is in the support, integration with other technologies, and unique design features that certain DAWs have chosen to specialize in. Reaper seems to be right down the middle and not specialize in any notable way or offer something that other DAWs do not.

For example, Ableton Live (a full-featured DAW that you can do every part of the production process in) has been designed from the ground up to primarily be a performance tool. It's features prioritize stability of audio, flow, ease of use, speed, and the ability to do powerful gestures with a minimal effort, all without stopping playback of the audio at any point. It's favored by musicians who want to improvise or get an idea as fast as possible and with minimal fuss.

In contrast, A DAW like Pro Tools is rich with features that allow for ultra-detailed tracking, editing, and mixing. It's very powerful in these areas, but lacking when it comes to sequencing or doing anything that favors electronic music.

Logic, on the other hand, is a jack-of-all DAW that sits right in the middle. It also comes with an exceptional array of plugins and instruments and a sizeable sample and loop library to get people started who don't already own a large collection of third-party tools. A great beginners DAW that you would never have to feel like you're missing out on by using.

Each of these DAWs have their niche uses. Reaper seems bland or undefined in this sense.