Well, my brothers didn't just get me the trailer with the cycling kit, they also got me the jogging kit, and I then went and bought the stroller wheels and the infant sling, all of which is necessary if you're going to use the device as a stroller right away, as opposed to waiting the requisite 10 months or so before the baby gets to wear a helmet and get towed along.
If you're used to regular stollers with plastic wheels, pushing one of the high end big wheel strollers will be a different experience. The wheels are pretty much the same as bicycle wheels, sized down and with fat tires. This does two things: first of all, bigger wheels bridge bumps and holes in the surface better, giving you a smoother ride. Secondly, bigger wheels have a narrower contact patch for the same weight, which reduces rolling resistance. High precision bicycle bearings reduce the rolling resistance even further.
The stroller is huge, since it comes with a roll cage. I installed the infant sling almost immediately, and luckily in the newer models it requires almost no tools and is easy to work. The difference between the stroller wheels and the jogger wheel is that while the jogger wheel is effectively a small bicycle wheel featuring pneumatic tires, the stroller wheels are solid rubber, and there's two of them mount inboard of the frame, as opposed to being an outboard wheel. The result is a dramatically smaller turning radius, with an increased rolling resistance. I practiced folding the stroller and unfolding it, and indeed everything does fold away very nicely, but it's definitely not something you can do without reading the manual. I was pleased with the side wheels' quick release mechanism, and how well everything snapped together. For instance, when using the jogger wheel, you can mount the stroller wheels inverted in the frame, so you don't lose them or outsmart yourself and hide them somewhere where you can't find them again.
Given that the stroller wheels are also very low in rolling resistance, why would you want the jogger wheels? The answer: so you can push the entire device off pavement on trails. Once you go off road, the pavement isn't as smooth, and the reduced rolling resistance of having only one larger wheel versus two small wheels is noticeable. Plus, you don't really want to be jiggling your kid in there. The stroller weighs 20 pounds by itself, but because of all the effects described above, feels much lighter: on level ground, I can push it along with just one finger, just as you would expect if you were pushing a lightweight bicycle.
The cockpit of the stroller/trailer is large, and has a canopy with a mesh window (to keep out the bugs in the summer), a sunscreen which can be deployed to keep harmful UV from baby's face, and a waterproof plastic sheet to keep the rain off, in case you decide to jog with baby in the rain. I'd probably get screamed at for doing that, so I didn't test to see how waterproof it really is, but apparently there's a separate water-proofing cover for people who are hardcore enough to take their babies out in pouring rain.
Obviously, it's illegal for me to take the kid out in it as a bike trailer, so I haven't tested it that way yet, but I don't expect it to be any different than other trailers I've tested in the past.
So, is it worth the price? Well, all in, the entire set up probably cost around $600, but we're using it twice a day for most likely the next 3 years or so. It truly is versatile, fits well, and so far, is the most consistent way for me to get Bowen to sleep. In fact, if he starts crying in the trailer, what I've learned is that it means he's asking me to speed up. Running with the trailer almost immediately puts him right back to sleep!
I looked on Amazon and used items are not available, and the lone ebay seller selling one used was asking $370 and $95 shipping, which indicates that the resale value on these devices would be comparable to that of a high end bicycle: unless you abuse the hell out of it, you should be able to get half of what you paid for it after 3 years. If you factor that in, the cost is comparable to that of buying a good trailer, a good stroller, and a jogger. In case you're interested, there's also a ski kit as well as a hiking kit. I consider the hiking kit ridiculous, and am not an enthusiastic skiier, so I can't imagine using the ski kit.
For now, my rating on this would be recommended. It's a quality product, albeit at a premium price.