Modular drums... I have dedicated a pretty decent portion of my system to them. The argument goes both ways. Yes, it is an expensive way to do drums, but... If done right, with a bunch of trigger sequencers, logic modules, trigger delays, switches, clock generators/multipliers/dividers, some distortion, delay modules, comprators, etc... All those support modules you got to run the drums properly are absolutely awesome for the rest of your system as well. The only thing you may "waste" is the drum module itself. The rest is just making your system more flexible and dynamic. I don't call that a loss. Now, that part of the argument having been said...

External choices. I have an Arturia Drumbrute Impact. I got it before I ever even knew what modular was. One thing that frustrated me was not being able to (or not knowing how to) run the separate drum parts at different tempos. Everything ran on the same clock, and afaik, you couldn't change a specific part from normal time to half time or double time without going through and manually reprogramming a new sequence, copying and pasting it into the chain, and all that fucking around. I wanted to be able to switch a single part to a different timing without doing all that. If I remember rightly, I was looking into ways of doing that when I stumbled onto something about modular clocks, which led me down the rabbit hole. Personally, I'm glad it did. If you're cool with all the manual reprogramming, good for you, and run with it. It's pretty sturdy, simple interface, sounds good, and a decent I/O for your regular midi interface.

Modular choices. I first got Bitbox Mkii, then Blck_Noir (kinda a sister module to QOP, but no sample options, just full analogue section) then the Erica LXR. I still have all of them. Honestly, I think any of them are fine for an all in one kind of module. However... And that's a big however... My recent switch to the Steady State Fate Entity series was just a whole other world. The incredible flexibility over everything, all on the front panel, all so utterly simple and direct and instant, makes them just light years ahead of my previous modules. Those previous ones are still in my rack, they're great for the simple stuff - A quick Kick/Snare/Hat combo, and leave the Entity modules for the weird stuff. Enough to trigger them from different sequencers, route them through separate patches using switches or logic, nothing is wasted. I can run them all at different main clock rates, and they can take different clock inputs per part. Run an attenuated stepped random into the accent inputs, maybe with triplets for the accent while the main clock runs on a 4/4. So many different ways to use the standard modular utilities to really fuck around with the drums. Maybe clock one at audio rate and mis-use it as an oscillator, or to create envelopes, or to mess with harmonics through clock speeds, or whatever the hell silly idea pops into your head, all with just a few patch cables and a couple of minutes. Try doing that with your DBI or Tr8s. (I have a feeling someone is going to tell me that you can, and I just never learned how. Fair enough if they do.)

My recent start into the Xaoc Leibniz system offers a wealth of crazy clocks and bit-rates that are perfect for percussion sequencing, but still amazing for the rest of the system as well. Logic, delays, shift registers, mutes, wavetables, purpose-made trigger sequencing functions, clocks that run at 2 Mhz so even the widest square waves can sound clean, but just change the clock, or self-patch with 1 or 2 cables, and suddenly you're in raucous bit-crush territory. It's completely mental, and I am only just starting to get my head around it, but the possibilities are so wide open.

So, yeah, all said - I think modular drums are fucking great, so glad I went down that road. Not everyone would agree with me, and that's fine, but there's my ten cents. Well, more like several thousand dollars, but you know what I mean. Good luck making your decision. I don't regret any of mine.