I am in a good mood this morning, So I will give some great info on this this. Yea the micro dolly can be more expensive, but it is worth it (see 1st link). Also if you are cheap, the 2nd link will show you a DIY for Dolly making.
Indie Dolly is a great well made portable dolly that I bought at NAB 2 years ago. The construction is excellent and it is very east to use. I looked at several dolly systems before I bought including micro dolly. Though they have a good system, it didn't appear to me that it could take a beating. Here's the Indie Dolly site: http://www.indiedolly.com/htmlfolder/IndieDollyFrameset.html