Just my 2 cents but buy a decent middle of the road set of calipers and a top end micrometer. Calipers are what they are and even the best set is not intended to be used for critical measurements. That's what a good mic is for. Rule of thumb, +/- .001 is pushing the limits of the best calipers money can buy and that's in a lab environment, used by professionals who do it all day, every day. Just look at the spec sheet, don't take my word for it.
Most of what we do, a good caliper is fine for but not everything. Some things, a micrometer is the correct tool and even the best caliper...just never designed nor intended for. Forget resolution! It means notta. Measurements given in tenths(.0001) with a caliper simply tells me the user doesn't really know what he's doing. Just being honest here.
With today's technology, you don't need to spend a lot for +/- .001 accuracy but if you need better, a good mic is the correct tool.
So spend $50-$75 on a decent set of calipers and spend about double that, or more, for a really good micrometer for the critical measurements that you need to rely on being right.
I use calipers every day. I use them for convenience to rough something in but when it gets nut cutting time, I switch to a good mic.