I recommend the Storm Streamline series bags or the Roto-grip bags. I had a 3-ball Streamline for a few years and it held up very well. The cups for the balls were nice and deep, so the balls didn't shift around unless you stood it completely upright. A friend with an Elite bag (possibly the same as the Brunswick and KR bags) complains that his balls move and shift in the bag even at normal rolling angles.
If you want a 4-ball bag, I like the 2x2 stacked bags over the inline-4 bags (like a 3-ball roller with a fourth sitting on top) because they're wider and, since they separate into two 2-ball pieces, easier to lift in and out of a vehicle. You don't have to lift 60+ pounds at once, you can do 30+ twice. My 3-ball Streamline had a tendency to tip over while I was rolling it if I came over a bump or curb not quite square to the drop. The 4-ball Streamline I have now has a much wider base and is not prone to tipping. The weight is also closer to the wheels, meaning less supported at the handle.
If I were to buy a new bag, I'd get the 4-ball Roto-grip one. It's similar to the Storm bag (Storm owns RG, and while Storm doesn't make the bags themselves, they're both made by the same company) and it comes in red. A guy here has the 4-ball one and with the very thin grey pinstripes on the red background, it's a very good looking bag.
SH
