I use the same Milwaukee. No issues with it at all for 2+ years. Was in dry storage for the last year and fired up without issue. Definitely budget but she works
I removed the bubble counter and hooked my line directly to the needle valve. Many screw up and put tap water in the bubble counter which ruins the needle valve and water can get back into the solenoid and cause it to stick over time. If you keep the bubble counter, only put rodi or distilled in it. On the Milwaukee reg, you need to run it at 35psi or so to maintain a steady bubble count and I would only use it with a controller as the bubble consistency is not perfect as sirreal63 pointed out but it is not terrible either if setup properly.
Last note, make sure you use a check valve off the reactor, many screw up and do not run a check valve. Saltwater can flow back into the needle valve and reg which really screws things up.