Well my favorite paper cutter is the Tonic Guillotine. It is sharp, precise, and I love that it has the cut lines as grooves and not painted on. However that cutter has limitations when it comes to cutting in very small increments.
So in conjunction to that I am loving my Fiskars sure cut. I love that it has 1/8 and 1/4 lines all the way down. The wire makes it easy to see where I am cutting.
I love my Fiskars rotary so much I bought two of them, one for home and one for my crop wagon.
It has the marks so I can automatically make mats in seconds. And the blades are so easy to change and go through several thicknesses if I need it to.
I have a professional guillotine I got from an art store - its rather large - about 3' x 3'. Gave it my son. No more guillotines for me - I jsut shread and tear the paper with them and I never get it straight.
I love the cutterpede because it's so easy to see exactly where the cut is going to be, the blade is easy to replace, there are decorative blades that are easily loaded, it is very easy to transport, the extension arm measures to 15" and it folds so it's quick and easy to cut an 8 1/2 x 11 sheet of paper in half, it has marks to measure every 1/16 inch, and it also measures in cm. It has a magnetic lock which holds the cutting bar in place. There are gripper feet underneath so the trimmer will not slide... I've let several people use mine, and I know of 5 people who have bought one because they liked it so much.
(You can also use a coupon for it at HL if there's one near you)
Fiskars is the perfect one for me. They make lots of styles. I can always find replacement blades and everything is a reasonable cost. I use my % coupons at M's or HL . I think it's important to get one that has easy to find and replace blades.
I have the MM trimmer and the cuttpillar pro. I hate the fiskars because they are not prescise, the blade moves in the track and you don't get a super straight cut. If you want a straight and accurate trimmer get the cutterpillar, love the edge light, etc. MM has a new one coming out so it might be worthwhile to try that since the old one is discontinued.
Fiskars as shown above. I just bought that one to replace the older version. The new blades don't move on the track with this one like they did with my old one. It also has the wire that I absolutely love.
I also have the small Fiskars guillotine since my CM personal trimmer was getting dull after 11 years.