logainofhades :
You get fewer PCI-e slots, not lanes.
My bad, I got the terminology mixed up. Yeah, the only two applications where I would recommend a micro atx over a regular atx board are if you are on a very strict budget, or if you are aiming for a smaller build. If you are doing the typical mid tower build and aren't looking to save space, I'd just go for the regular atx.
I personally think it looks better, considering it fills out the case a little more. I have a few mid towers with micro atx boards and the proportions look a little weird in my opinion. So add that to the fact that you are likely getting more features with the atx (depending on which one you buy of course) and I think it's kind of a no brainer.
HOWEVER, you are on a budget, and I think the builds logainofhades made look pretty good for your budget, and if you end up having to sacrifice the cpu, ram, or the gpu to get the regular atx, I definitely wouldn't do it.