I started out using a Lyman universal trimmer but quickly (very quickly) grew tired of turning the little crank. I then debated between getting an RCBS Power Pro trimmer or a Giraud and decided to save $100.00 and go with RCBS (with 3 way cutters for .224 and .308 cals). After about 1,000 (or so) .223 cases, I called Doug and got one of his set up for .223 Rem headed my way. I ended up buying a second Giraud set up for .30 cal just so I wouldn't have to "jack" with changing/adjusting the cutter and would have it set up, ready to go and got the shell holders for .308 Win and .300 Win Mag.
Now I'm not a rich man by any means, I'm just a poor old coal miner trying to get by. But my time is valuable and the Giraud really cut down not only on how long it took to trim 1,000 pcs of brass but also the amount of labor it took to finish each case. I've got severe Osteo-Arthritis along with alot of damage that was done to my right hand/arm when I worked in the Oil Field in the late '70's so anything I can do to cut down on labor involving my hands is more than worth the cost.
Using a Giraud, you can trim 1,000 cases quick but as has been stated, it has it's "quirks". It does use the shoulder to "space" off of but you still adjust the shell holder in or out until you get the desired case length so as long as your cases are sized the same, the length "should" be the same.....(I said "should"). And if you have 1,000's of cases to trim, I would recommend getting one. If you're only going to be trimming 100 or so at a time, I don't think it would be a good choice. I've pretty much come to the end of my bulk trimming stage and have about all of the brass I will ever use ready to go, so my Girauds just sit there on my bench now and what few pieces of brass I do need to trim, I use my Lee Case length trimmers to take care of.
I did just start shooting 300 BLK and am forming brass from 5.56 LC brass so the .308 cal trimmer will be seeing some more use. The formed cases are almost too short to keep a grip on when in the Giraud shell holder and they will spin when the cutter grabs them (another "quirk").
I can't comment on any of the other setups like the Wilson/Sinclair, WFT, etc... although I did start to get a WFT for 300 BLK but decided to just get the shellholder from Doug since I already had his trimmer.
That's just my opinion, so take it for what it's worth (although quite honestly, even my Wife doesn't care what I think).