Chiang Mai has a lot of shopping options. There are probably a dozen massive shopping emporiums located throughout the city. These places tend to be vast, powerfully air-conditioned, and have tons of stores. Ruamchok is none of these things.
The first problem is the fact that it is primarily outdoors. Although Chiang Mai is significantly cooler than other parts of the country (especially Bangkok,) it is still very hot by western standards. Therefore, the idea of running up and down stairs in the tropical heat in order to do some window shopping isn't exactly what I think most people would be looking for.
There are a few restaurants here including the usual suspects such as Mc Donalds and KFC, but they also have other nicer places such as Japanese and even Korean restaurants. The problem is, there are already so many of these sorts of establishments that this addition is not enough reason to come over here.
The entire establishment has this massive tin roof covering the entire top of all the shops, so at least you aren't going to get rained on. However, this leads to another problem: Ruamchok Mall is located next to one of the most heavily traveled roads in the entire city so this "rain guard" serves as an acoustic amplifier for all the road noise.
I likely wouldn't have even come here myself but I was riding my bicycle and couldn't figure out how to get to the other side of the 10-lane, divided highway and I was really hot at that point and figured i would stop in and get a double-cheeseburger because I enjoy health food. I walked around the interior and didn't even go into any of the shops. It really isn't a great establishment and I think that the local population kind of feels the same way because there were very few people here yet the Tesco parking lot across the street was nearly full.
If you are visiting Chiang Mai and want to head to a shopping mall for some stuff and some aircon / movie / bowling - I would say you can easily give this one a miss. I believe it was a poorly conceived idea that will eventually fail given the other options available in this sprawling metropolis.