Wyeast or white labs

has anyone tried side by side recipes, or at least repeated the same recipe, and compared Wyeast to White Labs? Recently I started brewing recipes with White Labs yeast that I've repeated several times before with Wyeast and I've noticed differences in how quickly (or slowly) they ferment but I don't know if it is just my luck, system or recipes. 1) starter solutions seem to take longer to step up. I like to step the starter up a few times, pouring off the "beer", to gather lots of yeast. With the same basic sterile wort solution and fresh yeast the White Labs seems to take long to complete the cycle and drop out. Some varieties (pilsner) don't drop well at all. 2) the initial fermentation (both starters and real recipes) seem to start faster with White Labs which is a good thing. I often see good activity in less than 6 hours. 3) fermentations seem to take much longer to complete As I repeat recipes that I have made several times before with Wyeast I can see a significant difference (days) in time to complete fermentation with the White Labs. Aeration, yeast nutrient, recipe, starting gravity, temperature - all as close to the same as I can control. As I think back to the first few recipes I tried with White Labs I do remember having to be very patient while waiting for the fermentation to complete, but I didn't have anything with which to compare. Somewhat like watching a kettle boil. If anyone else has experience with switch between yeast brands on a recipe, or other suggestions I'd appreciate the response. The faster start and the slower finish is what really has be confused. Since this is working out to be such a great basis for an experiment I think I will try the next step. One of my next brews I will try a side by side comparison. I will make starter solutions from each brand and split a batch to really compare differences (including taste) from what should be the same. Thanks Jonathan