Roomy (if not too tall)
Very quick to strike
Somewhat awkward pitch
Must manually seal seams (maybe)
Vestibule not included
More condensation than a double wall design
I have the previous generation, made of yellow fabric. It's essentially the same tent, but very slightly smaller. The photo is from a 2009 trip to the Yellowstone NP, Electric Peak area.
I've used my HiLight in a variety of conditions, including summer and winter in the Colorado Rockies, fall in Yellowstone, spring in Grand Canyon, and hot, humid conditions in the Boundary Waters Canoe Area Wilderness. Simply put, this is a great three pound, four season, solo solution for all but true mountain or arctic conditions. Even then, I suspect the HiLight is sturdy enough to survive where other non-mountain rated tents would fold, but I don't believe it's truly designed for serious mountain use. I'd say the HiLight is best described as a four season, alpine tent that works well in most conditions. If you want a true montaineering tent, BD's Bibler Ahwahnee Tent offers a similar configuration built to a much more rugged spec.
I'm 5' 10", 180 lbs, and with a 2.5" mattress, I have plenty of room for myself and my gear. The ends slope inward enough that mattress thickness affects actual sleeping space. The new (current) model is longer, but folks over 6' tall should check to see if the tent will work for them on their mattress. One end of the tent is slightly wider than the other. If two people squeezed in, the wider end might be a little better for two sets of shoulders. I've never tried to squeeze in a friend, but two people with two pads & bags could work if it had to. I think it would best be avoided unless you're both pretty small or very familiar. Adding the vestibule would help, but the interior of the main tent would still be cramped for two people.
Pitching a single wall tent with an interior pole design can be a challenge, but it's manageable (see my video link). I find it easiest to pitch it while standing the entire time. Without pole sleaves, it's important to keep the poles seated in their corners until finished, and I find it easier to do this standing than while flopping around on the ground. Another advantage to standing is the tent basically becomes a rain poncho if you're working in bad weather. I saw a review elsewhere that mentioned trying to use the small fabric loops as pole guides, but I think those are intended to be hang points for gear. The interior pole system makes it very easy to tuck lots of clothing up for drying. The HiLight is more difficult to pitch than the typical double wall, external pole tent, but it's not a big deal to me. The design strikes very fast, which mitigates some of the hassle of pitching it.
Sealing the seams isn't difficult, but it must be done, at least on the old model. BD used to include a tube of sealer with the tent, but I'm not sure if they still do, or if the new, green model requires manual sealing. The only time I've had any condensation to speak of was when I fell asleep without opening the vents. Fortunately, it all ran down the sides and collected in the corners, so it was easy to mop up. The new, green fabric may offer better breathability.
I mentioned that this is a warm tent, but it's still useable in hot weather. With the window flaps both open, ventilation is adequate. The advantage of being such a warm design means you may be able to pack a lighter sleeping bag than possible in a tent with some exposed mesh panels. I've seen the HiLight described as both a 3 or 4 season tent. IMO, its pole configuration makes it strong enough, and the ability to fully seal it up makes it warm enough be considered a true 4 season tent.
BD ships the tent ready to use (except possibly seam sealing), but I've enhanced my HiLight in a few ways. An XS size Sea to Summit sil-nylon compression sack can suck the tent down to a roughly 7" ball. MSR Needle Stakes are very light, rugged, and much more compact than the included BD Y stakes. MSR Blizzard Stakes work great in snow, and are likewise light and compact. I replaced the guy lines with Kelty Triptease for better strength, visibility, compactness, and lighter weight. I've been using a piece of housewrap for a footprint, but I'm ordering the BD footprint to save a little weight and bulk. I'm considering some aftermarket, carbon fiber poles to shave 6 oz, but they aren't cheap.
For me, the HiLight strikes the right balance of features at this pricepoint. I have no regrets about buying one, and I plan to use it for many years.