I have not had a lot of time to ride (nor warm weather, though the trails at lower elevations are amazingly still dry) so this post doesn't have much to do how my new singlespeed rides. Instead, it's about the dropouts - which I have gotten a ton of questions on.
If you're too lazy to read my ramblings in full, suffice to say that I think the Paragon sliders, as of now, are a better option. Here's why:
-The Black Cats aren't stainless. This is a pretty big deal to me, since you really need metal to metal contact to keep the dropout from slipping easily. Hence you've gotta leave at least some of the dropout unpainted - and that means (eventually) rust. A big deal to some folks, not such a big deal to others (here in CO, it's not an issue) but a serious downer on a dropout that costs $150/set (for reference, that's 50% more expensive than the Paragons, which aren't cheap).
I assume they're non-stainless to allow easy fillet brazing, but IMO this is a silly way to do things. Fillet pro would work fine if you want the fillet look, or these could be re-done as a plate/tab style dropout and they could be silvered in. Obviously for TIG guys/gals, an identical version in stainless would work fine.
-Set screws aren't integrated to the dropout. If you look closely at the picture, you'll see a small hole in the hood - that's where you're supposed to weld or braze an M4 eyelet to allow the set screws to be used. This is a PITA to do (I've heard of them popping off under load if brazed in, and if you TIG them like I did on my frame, you wreck the threads and have to do a bunch of work to re-tap).
-All the work is done by one bolt. The upper "pivot" bolt doesn't do much to keep the dropout from moving at the axle end due to the leverage involved, so really there is just one bolt (plus a set screw) on each side keeping your wheel in place. This has worked fine so far, but I worry that if that bolt came loose and wasn't noticed soon enough, the set screw would get bent/damaged and have to be extracted (giant pain). Again, the non-stainlessness of the dropout is a contributing issue, since the force needed to clamp the dropout in place is very high. That's a lot of torque on one (admittedly, big fat M8) bolt.
On my first two rides, the rear end of the bike came completely loose. I fixed this by using IRL-grade loctite on all the M8 bolts, and it's been fine ever since. So perhaps my concerns are unfounded.
-Finish quality is mediocre. They're ok, and it's not a big deal, but it's lame to have to bevel all the edges and corners yourself with a grinder or a file. It's not that hard or expensive to finish the piece nicely - especially given the price.
So far, my only complaint about actually riding with these dropouts is that they seem to correlate with incredible rear brake howling (yes, they're Avids, so it certainly could be the brake at fault, but the same brakes haven't had this problem for me on other similar bikes with different dropouts). I have heard from (trusted) fellow builder friends that under heavy braking, the wheel can move the brake side dropout *backwards* enough to cause problems, though this isn't something I've experienced.
However, they look cool, they have a nice range of adjustment, and they let me tension the chain - so far, they're doing their job.
With all that said, if I were building a new bike for myself today, I would go back to the Paragons. They are tested, reliable, and don't have any of the problems/issues that the Black Cats do - plus they're actually quite a bit cheaper and equivalent weight.
I'm happy to build with any dropout a customer wants, of course, and my whining here should be taken for what it is - niggling complaints about a very cool product. Black Cat should license the design or have some stainless models made, improve the finish quality, and incorporate a better set screw setup, and I'd be an even happier camper.