I realize it's sort of odd to review a router bit, but this is a little different, and I want to talk about the results of the technique as well. This is what we're talking about:
And it's available here:
http://www.amazon.com/Grizzly-C1191-1-22r-Roundover-Shank/dp/B0000DCZ3R/ref=wl_it_dp_o_npd?ie=UTF8&coliid=I2V8B49RGSAU2W&colid=2X6XWUI2ZPMSL
The idea is to get a rough shape to your neck for the sake of consistency and saving time.
Regarding the bit itself, I was surprise at it's quality for the price. These 1" radius bits can easily cost $100 or more, so for $31.95, I think it's a bargain. It comes very sharp, and there's a lot of material to the bit. It also has a replaceable bearing. The only thing I don't like about the bit is that it's not carbide tipped. I guess you get what you pay for. It performed well. I had a very small bit of tearout in one spot, and I was working with a Bubinga neck. I find I get a LOT of tearout with Bubinga, and it's best worked with sanding and grinding tools rather than cutting and carving tools. So I was pleased with the fact that I only had one little bobble, and in fairness, I was taking off a little too much at a time anyway.
Regarding the technique, I think the most important thing to note is how much time it saved me. A couple simple passes on each side and I had a guitar neck. Twenty minutes or so with course sandpaper, and I was done, except for a few details at the volute and the heel. I like a really thick neck, about a full inch thick, so this seemed like a good solution. And it works as you'd expect. If I ever wear the bit out, it's likely I'll replace it with something similar, or an upgrade.
Router rails and a mess of clamps are required to do this correctly. If anyone has questions, I'd be glad to help/clarify.