I used my store bought for a month before I got my first GuHong. When I got the GuHong, I couldn't even use it because my finger joints were killing me. I only had to look at a cube, and my hands would start hurting. Using the store bought put me out of business for about a month and nearly put me off cubing altogether because it was also influencing my guitar practice.
Since I dumped the store bought, I have no problems with pain what so ever.
I get what you mean though, you're suggesting optimization before moving on. But a store bought can really mess up your hands if you use it as much as a beginner would.