Yes, I've heard this, I've always heard that facing South, or East are preferrable, I think that's because of them getting the morning Sun. I think the one thing most people try to avoid is facing them North because of the wind and winter issues.
I started with mine facing South, added a few more hives and put those facing East, and had a couple more late addtions that I ended up facing North...I'll probably try to reshuffle everything come spring, in the mean time I've just put a wind block in front of the two Northern facing hives.
Hope you and your bees are doing well!
Along the lines of what Coates is saying...I'm not convinced it really is that big of an issue, but I do think avoiding facing them North probably has some merit. If I rearrange, I'll probably end up with half facing East and half west, just because I think that will be the best layout for where I have my bees.