I use IEMs for practicing and ear plugs in almost all other situations. The ones I have are custom molded by Future Sonics. Supposedly their IEMs have a bit more low end for drummers. I have not tried any other brands. I expect most of the ones available are decent. The high end Future Sonics IEMs allow changing out the attenuation insert so you can let in more or less ambient sound.
Custom ear plugs, especially with variable attenuation inserts, are a hugely valuable investment for any musician. At least for those who play in any situation where music is amplified. (Or drums are involved :-)) They are also great for just going to concerts as you can hear the music accurately, but it isn't too loud. I usually use the ear plugs with no attenuator installed during practice, which is like 6dB of attenuation IIRC. Not that much, but enough.
I use IEMs for practice and have not used them on stage. I've talked to folks who play in bands that use IEMs for monitoring during performances. The main issues are making sure everyone using them has their own volume control, latency, and having something that sets up without hassle in the venue. You'll also need to make sure they feel good and don't get in the way, but that just a matter of getting the cable tied down to the throne/etc. in the right way, and figuring out where you want your local headphone amp, etc. The impression I get is that for bands who perfect IEM monitoring, they totally love it and would not go back to wedges, etc.
Sophisticated setups allow a separate mix for each member of the band. E.g. they get more or less of their own playing. Similar to standard stage monitors. If it is just you, as the drummer, using IEMs, then you can likely control the mix of the drums via the ambient attenuation of the IEM itself and a volume control on the input to the IEMs. A simple feed of the sound board mix is all you need. (Latency gets to be a thing in studio setups where you're listening on the backside of the DAW, etc. It is doubtful you want any effects on IEMs live anyway.)
I've experimented with micing the drums and mixing them and listening via the IEMs. One can definitely get great drum sound this way, but it is a lot of work and not that useful unless you're recording mostly on your own and need to hear the set as the mics do.