At present, there is still nothing quite like the Machinedrum (UW or not). That makes it still relevant - more so than yet-another-808/909 clone or inspired machine. More so than yet-another-purely-sample-based drum machine.
I think in terms of synthesis options, the best modern competitors are the JoMoX alpha base? Nord Drum 3 (which has no sequencer and is only available with annoying drum pads)? The new Korg Volca Drum looks like it will bring some cool digital drum synthesis techniques back to the larger market too. Maybe the DSI Tempest is out there as another rather unique synthesis based drum machine, but it’s still priced way too high and still seems plagued with problems.
As for relevance in regards to ‘popular’ artists - the Machinedrum’s best era seems to be about 10+ years ago. Autechre, The Knife, etc, all used it quite heavily from 2005-2009. But you still see it used by the likes of Venetian Snares and Thom Yorke.
Anecdotally, I have a friend who bought one of the original Machinedrums when it came out who still uses it quite heavily in multiple projects (most of them industrial/power-noise related). It still seems quite relevant to him.
The combination of synthesis options and the ability to blend them all together to make a unique kit seems nearly unequaled. You can have fun combining the PI (physical modeling) kick and the EFM kick (using trig grouping), for example, to make a large noise.
Is the Machinedrum a bit dated? Yes. But today’s dated is tomorrow’s retro. Cool digital drum synthesis options have been rising in Eurorack, and are starting to return to larger market (Volca Drum), and I wouldn’t be surprised to see more coming in the next year or two. In this regard, I expect the Machinedrum’s status as a ‘classic’ start to rise even more.
But it also puts one into wondering - buy now, or see what comes over the next couple of years? I say it’s still worth getting now.