I use the Kelton hollowing rig and have been extremely satisified with the system. I initially chose it over the jamieson type and other systems because my shop lacks wall space to hang things like D-Bars, Y-bars or whatever. Without the laser guide, the Kelton rig stores very compactly on a shelf. Now that I've added the laser it's not as compact, but I'm still very happy with my choice. The laser on the Kelton rig does not vibrate anywhere near as much as the laser on other systems that use a single vertical rod to support the laser assembly.
I found the laser a little fussy to adjust at first. Tightening the screws would cause the laser to move, changing the setting. I found through trial and error that tigtening the four screws in a very specific order allows me to set the laser with no more fussing.
I find that I can hollow to 8" very aggressively with no problems. I can hollow up to 12" with the area from 8" to 12" requiring a very light touch that took me a while to develop. Anything over 12" is beyond my abilities with the 3/4" cutters.
Once I got my rig setup just right, I cut 3 lengths of pvc pipe to use as spacers. One goes over the tool rest post and the other two go over the uprights on the rig. The whole system can be assembled and cutting in just a couple of minutes. I don't have to leave it assembled to preserve the setup when I'm not using it.
I use a good quality diamond hone (the type Alan Lacer sells/uses) to sharpen the cutters. A couple quick swipes is all it takes to sharpen.
In my experience, Kel McNaughton stands behind his tools 100% and is a heck of a nice guy. He's in New Zealand. When I first got the system I had a few questions and emailed him. He tracked down my phone number and gave me a call from New Zealand to anwer my questions. I was shocked to say the least. As pointed out above, he is also very responsive on email.
Ed