I'm probably the least qualified to critique a sans design, but I will attempt it anyway. To my eye the horizontal weights are a tad too heavy for the verticals. The verticals need to be slightly heavier than horizontals to balance out optically. This is most noticeable on rounded bottoms like the nine or five.

I am no expert either, but I agree with Stephen.

I am no expert, either, and I agree with both of you. The verticals were a bit heavier, but clearly not enough. I addressed that issue and made some other tweaks.

I added the file to the original post.

thanks!

You made the 7 a little too heavy.

It seems to me that the top of the 2 is not quite fitting the overall style; it's narrower and rounder than expected.

This is pretty successful.
Bowl of 6 looks a bit small next to the 5. Diagonal on 7 looks heavy. Make the hat on 1 longer? Curves on 0 look a bit flattened perhaps.

Thanks!

Right after I posted the last version, I noticed that the 7 was too heavy. I think I've got it looking good now.

If the bowl of the 6 looks small, I assume the same for the 9?

Well it's hard to say because of the numerals in sequence like that...9 is next to 8 which has smaller bowls than the 5, which makes the bowl of 6 look smaller. It'd be easier to tell if you did a sample with numerals all mixed up I think.

Are these to go with an alphabet?

Ahhhhh, good point. I'll mix them up the next time I post them.

Yes, these are to go along with an alphabet (more or less).

They're part of a font that's just numbers and uppercase letters placed within circles. It's hardly an original idea, but all the stuff out there wasn't to my liking for some reason or another. I need to label diagrams for my job, and I wanted something that was neutral, and was also easy to use. So I figured I'd come up with my own version. I'd get everything the way I wanted, and it would a good learning experience.

I was thinking the letters looked really good, but some of the feedback about the numbers will apply to the letters, so I'm going to clean those up some more and post them as soon as I get the numbers finished.

version 3 is in the original post