I don't review many items, but I'm big into running and I know how big of a decision selecting the right shoe can be. I personally get frustrated when I find a shoe I love, only to buy it two or three times before it is essentially unavailable in ANY color in my size. Then I'm back to the drawing board. So here's the review. FWIW, I'm 6'4", and 190lbs. I run about 100 miles per month. I have a neutral stride. I run a decent amount because I like IPAs and cheeseburgers.I absolutely LOVED the pegasus 33. I had a history of knee pain on runs that went longer than 5 miles. For years. When a buddy talked me into trying a half marathon, the 33 got me to train for 13.1 relatively pain-free. A few months after the half, I did a full. The 33 was the shoe that got me through. Maybe a tad bulky, but comfortable, padded, and reliable. I bought a new pair before my first marathon, wore it for 2 short runs, and used them for the full 26.2...out of the box, the 33s were just like running on the clouds. However, every 250 miles or so, I'd have to replace them. Did a few marathons and a few halves rocking the 33s in whatever color scheme was left in my size online. Last year, there was not a 33 in a size 12 to be found. I had to try the 34s.At first, I absolutely hated them. They felt less padded, and there was a pronounced spot on the side of the shoe that caused some serious discomfort. I almost sent them back. After getting 1-2 miles into a run, the discomfort would sort of ease off, and then it was fine. But I have to say - after 50-100 miles or so, they really got comfortable for the entire ride. Moreover, they lasted almost twice as long as any shoe I've ever owned. I just bought another pair of 34s after 400 miles on the last pair.I don't know if there was a serious change to the way the shoes were designed, but I found the 33s to be soft, pillowy, and comfortable out of the box. But at around the 200 mile mark, I could really feel the 33s breaking down. On the other hand, the 34s feel lighter, yet more rigid - and they can feel uncomfortable out of the box. But for me, once they were broken in, they were a terrific shoe that lasted a long time. If you loved the 33s, then you'll probably find the 34s to be different - but after a rough start, I really grew to like them.