I own pair of Lowa Tibets, Baffins, and sheep hunters. Have also owned a pair of Meindls.
As far as comfort I would rate them the following: 1) Baffin, 2) Tibet, 3) Sheep hunter, 4) Meindl. As far as break in period is concerned I was not happy with the Meindl's at all. The Baffin, and Tibet require a little break in period but not too bad. The sheep hunters are a fairly stiff boot that requires even a little more. I really like a taller boot and the sheep hunter is taller than the other two lowa boots but also has 200 grams of insulation and is rather heavy.
I always thought that Lowa was the best of the best for a good hunting boot until this year. This year I was lucky enough to try out a pair of Schnees Beartooth boots. This boot has become my favorite boot big time. A few of the things that I really like about this boot are; they have a more supple leather that does not require hardly any break in period, it's really soft but seems very durable. They are also the same height has the Lowa sheep hunter. On paper they weigh about the same as the sheep hunter but they feel far lighter on my feet. The rubber guard around the boot also wraps further over the toes on the Beartooth, I like this feature, it provides a lot more protection when crawling and hiking. They can also be re-soled.
I have not had the opputinity to try out any of the kenetrek boots, but I have friends that speak very highly of them.
Price wise they are all pretty close.
One other thing to consider is that Lowa made some changes to the design of the Tibet a couple of years ago. At that time you could find a pair for around 200 bucks. You still might be able to find a new pair of the older designs somewhere on the web. It seemd like the common sizes sold out pretty quick, but it might be worth a look.