Since I got my first pet stroller, I've become extremely stroller aware. I study every stroller I see, and I have come to truly appreciate the choice I made. I bought two others almost immediately after the first, and have driven as many others as I can, so that I can speak from experience. I still am in love with my original stroller, and have sold the second. The third is pretty much a joke, so it serves mostly as an elevated pet bed in my living room. As I write, I have six strollers in my living room and two in front of my door, at the ready. Only three are regular baby strollers--I've become a stroller addict.
There have been plenty of comments I've heard about cost, and just like baby strollers and our own motorized strollers (cars), paying less can truly cause problems. The words "deluxe" and "luxury" seem to be used like "natural" had been in the food industry--pay attention, read carefully and ask questions! Don't be fooled by what some may claim are retail values or prices, because plenty of what is sold online is not actually sold any other way, and those numbers are quite misleading. PLEASE, don't buy an inexpensive one "just to see if Fluffy likes it," because a poorer quality stroller just might be the problem.
That said, there are some very important considerations when choosing a pet stroller. This is a growing and young field, and there already exist "knock-offs" to take your money and let your pet down. Choose well, because if what you buy is not something that you enjoy using, your pet won't get to much either, and you may end up spending more money than you ever would have, had you gotten what you needed in the first place. What most never talk about that I have found to be crucial are suspension and height, both interior and from the ground. If your animal cannot move around, sit up, stand, etc., there isn't much improvement between strolling and being crammed into a carrier only to get to the vet. Weight capacity in existing pet strollers ranges from 20# to 165#, but don't let that be your primary consideration. For smaller animals, getting away from where big feet and other hazards are, and closer to their humans' faces and voices is comforting, and greatly enhances the feeling of security on a stroll. Most of the less expensive and smaller pet strollers have no suspension whatsoever, small wheels, and are very close to the ground. Two days ago, I had occasion to actually stroll with the second stroller I bought, and I learned that the bigger problem with having no suspension is that your hands will bear the brunt of a rough ride. In about two and a half months, I estimate I've strolled over 250 miles with my Pet Gear AT3. Had I tried to use the second stroller in real life, I think I would have stopped after ten minutes and had to buy something else. It took work to keep the stroller on a path, and my hands hurt from the effort and extra vibration. Granted, the wheels on that one (sold here on eBay) seem to belong on a toy, not a vehicle for actual use, but when does anyone even describe the wheels unless they are good? Think about it.
The third stroller I purchased, I have and still describe as a joke because it is pretty, but not at all rugged. (I've written reviews of each of these in my PetStrollers yahoo group—everyone is welcome to join!) If you have a sedate little dog and you're content to just look cute cruising a mall, you might be alright with the Formay line. I would not trust it to any uncertainty at all though, and the leash clips in it are clearly essential—but why do you want to have to tether your animal IN a stroller? The top of the stroller enclosure is only connected at the back by one piece of narrow velcro, the mesh is so soft it could get shredded the first stroll out, and the main fabric I'd expect to find in a casual windbreaker or less. I guess it should have been a clue that I was offered this stroller for almost $30 less than the winning bid in that listing. My cat loves to sleep in it though, so she got a new bed. --I actually took this stroller out for a full test ride and was appalled. Front wheels fell off twice, and although they are made of decent material, they are small and don’t all touch the ground at times, and this stroller had me cursing and irritated! The passengers (a cat and kitten) were noticeably less comfortable (other people's observation!!) and became disagreeable, which was very uncommon for them.
Pet Gear has the experience of making baby strollers, and even a cursory study of the models bears this out. Unfortunately, the Happy Trails model has been knocked off (by Pet Coach and others) and is attempting to pass as an AT3, which makes no sense at all. Putting two front wheels together does not make a stroller an "awesome handling" three-wheel vehicle, especially when the weight of the stroller and the weight capacity are only half of what the real thing offers. I chose the Pet Gear AT3 based on stability and maneuverability, but I also put some kids in one to try it out. If you don't want to spend much, go for the original Happy Trails, Happy Trails Plus, or new Jeep Wrangler Pet Stroller, and if you want more out of your life with a pet stroller, get an AT3. The Ultralight is a better small model that any other I have seen, but it does not have the suspension of its older siblings. For about $20 more, you can have happiness on wheels, and for $100 more, you'll have heaven. If not the Cadillac, the AT3 is certainly the Lexus of pet strollers. And for those who think they will be self-conscious about strolling a pet, the AT3 has fooled many, even vets up close, who are sure I'm strolling a baby!
14June06 update: The world of pet strollers has been graced with the addition of the Pet Gear Jeep Wrangler Pet Stroller and the Kyjen Walk N Roll in pink, both well-established companies. Neither is being offered by eBay sellers yet.
Amazingly, there IS a pet stroller new to eBay that I've become acquainted with that rivals the AT3. (I've written a lengthy review of the Ibiyaya in the PetStrollers yahoo group) Unlike the AT3, the Ibiyaya is not all-terrain, nor very large (~40# capacity), but for most, who will only be strolling a single animal, it will serve quite well. The surprising thing about it is that it will actually fold with the cabin zipped--it just compresses--so if you have a small animal, you could conceivably get to the vet in the car with just this unit. I'm a tough customer, and I was really impressed! (Remember, I don't sell them, I just buy them.)