Craig,
Overall I would say yes - well worth the effort. I know of major problems/lack of support with other boards/controllers, including dedicated controllers (Adtech in particular), so don't regard my experience the XHC controller as overly troublesome. With regards to lack of support, I've actually had more issues with ArtSoft who refuses to acknowledge an issue/undocumented feature with Mach4 (I use metric, and if I go into config to check a value (ie not change anything), when I come out of config the units always revert to imperial even though G21 is active ... so a 10mm jog gives a 254mm travel!! I need to exit and reopen every time opening config - despite claims to the contrary). Not a major inconvenience once you know about it, but I did break a few tools until figuring out the glitch - which must surely affect others. The other issue is with Mill Wizard. Purchased last ~August, but unusable because it will not accept the key supplied. I've given up trying to get a new key or advice on what to do.
With XHC, I actually tried to purchase this controller (the new 6 axis version for Mach4) before it had been properly released and was happy to wait a few weeks for the final debugging - so knew that I was one of the first to purchase. In the event it arrived before my machine, so my first task when the machine arrived was to remove the Mach3 controller supplied and replace it with the XHC Mach4 version. Although a complete novice with CNC, the install and Mach4 config was straight forward. The XHC manual is very easy to follow. The machine worked fine for the first few jobs, but then I started to get the occasional missed step accompanied by a grunt from the steppers. The G31 macro was also not giving reproducible tool lengths. XHC were initially quite dismissive of the controller having a problem, and instead insisted that the problem was my setup - reasonable given the vast array of setups possible and novice users like myself. In the end I recorded the diagnostics screen whilst probing (using the screen record function in PowerPoint) and sent this to XHC. They responded immediately, and we ended up having a couple of Skype and TeamViewer sessions with their software guy which showed problems with both the controller AND my computer (although its a high performance laptop, I was using an appropriate USB cable and had too much other junk running in the background which were causing USB timing issues). XHC provided an updated driver for me to try within hours which together with my tidying up my hardware has solved my issues (almost). My only gripe is that G31 is still not as consistent as my own step on-off-on.. probing macro. It occasionally is 1 or 2 microsteps (0.00625mm or 0.00025" steps) out. My macro is always spot on. The simple solution is to only use G31 for the initial rapid probe to the guess length, then revert to my step method. This is actually slightly quicker than running a G31 at a low feed rate for the last (say) 10mm.
I've tested the controller with a number of repetitive tasks and then checked to make sure that the actual final position is as commanded by Mach. This included drilling a 2mm sieve plate. All good.
My main recommendation to anyone having support issues is to obtain screen dumps or a short video of the problem to enable the vendor to make an informed comment. "Occasionally missing steps" isn't very helpful as I soon found out.
Best regards,
Louis