About six weeks ago I threw out a question to the forum about heated grips and handguards versus heated gloves for cold-weather riding. Since then, I added Hot Grips heated grips and Barkbuster hand guards, and this past week I've finally had some colder weather to put them to the test, so I figured I'd put up a short review for posterity.
I can't speak to the ease of installation, since I had George put them on for me (and he seems to have done his usual outstanding job), but he didn't complain about them to me so I hope they weren't too difficult.
The Hot Grips with a high-low toggle switch (a valuable add-on versus the basic on-off button) work quite well. The high setting puts out noticeable warmth within about 20-30 seconds, and is fully toasty very quickly after that. The toggle switch was absolutely worth the extra couple dollars; when I first get on the high setting gets my fingers warm, but the low generally keeps them warm once I am going, and using the high setting when it is only cool out rather than cold doesn't work as well as just putting it on low to give my hands the little extra boost. What I have found though, is that your choice of gloves really makes a difference. With thinner summer-type gloves, the heat is really transmitted well, so when it is just cool they work well. With insulated winter gloves the high setting works well because it transmits heat okay, and retains it well. What doesn't work well, in my experience so far, is thicker uninsulated leather gloves; they don't transmit the heat all that well, and without insulation they don't retain it either.
The Barkbusters seem to be pretty important in using the insulated gloves effectively. Before I had them, I found that the wind cut right through the insulated gloves, particularly the finger tips, and especially the thumb, since they face the wind. The Barkbusters feature a pretty big wind-break attachment to the actual metal hand-guard (they can be adjusted to be smaller or taken off entirely in the summer), and they are offset downwards, which really helps with the thumb issue.
Overall I've found that the combination works as well as I'd hoped; I've ridden for more than an hour several times now at 32-35 degrees, and my hands have been just as warm when I got off the bike as they were when I got on. If you get cold easily or want to ride for longer periods in sub-freezing weather, it's probably worth the money for the Gerbings setup, but if you're just looking to keep your hands warm in the 32-40 range, then Hot Grips and Barkbusters are probably a good (and less expensive) option.