RE: Which one? Black Diamond or BigHorn?
I have two Black Diamonds and don't consider them to be unduly troublesome to clean. I use musket caps. Usually clean in a bucket of hot soapy water with the breech plug and striker assembly out - submerge the whole action in the bucket. Then rinse and blow everything out with a high pressure air hose.Cleaning takes about twice as long as my new Omega, but its still not a big job.
I also think the Black Diamonds shoot well with both sabots and conicals. I had Knight Disc Rifle up until recently and it was a lot more particular about loads. Triggers are very good on both guns.
Have seen Black Diamonds on sale for under $200.Get an XR in stainless if you can find it.