My 30+ history of trimmers: I started with an RCBS crank trimmer, an old style they don't make anymore. It worked fine for the small quantity of brass I could afford back then. But when I got my first big sack of once-fired LC in .223, I knew that crank wouldn't cut it anymore. I rigged my own converter to turn that trimmer off an electric drill. That worked fine at first but the locking mechanism that set the length wasn't made for powered use and it tended to slip, making my cases shorter than I originally set the machine for.
Then I tried the little Lee trimmers. Several things: The cutters are cheap (what do you expect for under $10?) and get dull real fast. Bigger problem: The caliber-specific cutters set their length by using a pin that runs down through the primer hole and indexes off the shell-holder base. When you start doing volume trimming with a drill on the cutter end, that pin will drill a little pit into the shell-holder base, thus shortening your cases more and more as the pit gets deeper. After going through several bases, the Lee trimmer went into the trash. (Besides, you couldn't adjust your length.)
After trying another crank style or two, I bit the bullet and bought a
Gracey (they were about $75 cheaper back then). I now have three of them. They are a PITA to adjust when you change calibers (thus three of them for my main calibers) but you get the knack after a while. They chamfer and deburr at the same time they trim. It's like sticking the case into a pencil sharpener - about 3-4 seconds and you're done. You're not stuck with some pre-set length either, you can set it at whatever makes you happy (there's nothing magic about the 'trim to' length - just a way to shave off more than needed, especially if you trim after every firing to keep things consistent case to case).
Last year I bought a Giraud. It is fancier and 'slicker' that the Gracey by far, and it has some advantages and some disadvantages. The main thing I don't like about the Giraud (other than the price) is that it uses a single V-shaped cutter, and that cutter leaves a sharp knife edge on the lip of the case mouth - something I was always taught to avoid - and isn't a proper cut the main purpose of a high-dollar trimmer?. The Gracey has two cutter blades and you can adjust those blades to get a flat lip on the case mouth, 'flat' except for the amount of chamfer and deburring you want. You can also adjust the blades when switching between thinner-walled cases or fatter-walled cases (like Win .308 at 0.011 to LC at 0.016 in neck wall thickness). You can't do that with the Giraud; it just gives you a thicker knife blade.
There are more pros and cons between the two powered machines. The Giraud is really nicer in many respects than the older, more crude Gracey design. But I can't stop using the Graceys. If I were a machinist, I would build a Gracey-type cutter head that would fit on the Giraud. There's no reason why it can't be done. Now that would be the best of both worlds. And oh yeah, something to quiet that screeching noise the Giraud makes. The Gracey runs almost silently. (But the Gracey also tends to throw oil out into your table.) And the Giraud is just as hard to adjust for a new caliber as the Gracey. The instructions tell you that several cases will need to be sacrificed in that process. The Gracey is much easier to adjust for case length.
For the oddball calibers that I don't shoot much, I just use a Wilson trimmer from Sinclair with a drill adapter. The cost and hassle of setting up a Gracey or Giraud isn't worth it for just a few cases. And the Wilson has shell-holders for those odd calibers without a shoulder, like 30 carbine or 45-70 (although those rarely need trimming).
I could talk more about the Gracey vs Giraud comparison, but I figure your eyes have glazed over already. I've never tried some of the other trimmers on the market today, like that World's Best Trimmer.
