I personally use Chrome exclusively. I don't even have firefox installed. Why? Well two major reasons:
1. The embedded flash in Chrome is MUCH more current (v21 vs v11 in firefox)
2. Chrome is still the only browser that allows Netflix to be watched out of the box
It is a memory hog for sure, but if you have enough memory it shouldn't be a concern. I have 8GB and I have seen Chrome suck as much as 1.5GB when really putting it through its paces.