Pros: Effective. Minimal space required. Good value. Durable; safe to use, no spotter needed.
Cons: Not much. Prices down, resistance different but equal to free weights.
First, I want to bring up the effectiveness of the Bowflexes, from the Ultimate to the Elite to the Sport. I mention this because upon reading the reviews you'll invariably find some who disparage it for several reasons. As a long-time weightlifter who has been using a Bowflex for some years now, I feel it's important to address these comments:
"It has a strange feel that is unlike free weights". Actually, some prefer it to the feel of free weights; i'm in that category. Intense; often more rigorous and continuous tension akin to pulleys. Closest analogy is to rubber bands; takes a week or two to aclimate to it. Feel the burn!!
"It's no good for legs". IMO this should be interpreted as (1) they didn't understand that they can buy more resistance, (2) they're the 1% of the population who are bodybuilders requiring more than 410 lb. for legs (extra, 3rd party band resistance can be bought and used to increase the weight to above 410 lb., BTW, for the few who need it).
"Free weights are much cheaper and better". Bowflex prices are coming down as of late as more models (with more durable construction) become available. Ultimates now go for around $800-1K used on Ebay. While a dumbbell set and bench is useful and cheaper, an Ultimate does in fact provide a much wider array of exercises to do, many of them quite effective and useful.
"The Bowflex is only good for toning". Uh, no. This is laughable IMO. Bottom line: if you increase resistance on this you will gain size, period. If you do more reps, you'll tone the muscle, if coupled with a good diet.
Several years later i'm still impressed by the Ultimate. Any number of exercises can be done, in about the smallest amount of space possible. On space, keep in mind that Bowflex also sells the Elite and Sport, which cover much of the ground of the Ultimate, but they don't fold as small, which is important for some including many in apartments. The convenience of it's wheels is no small thing BTW; once folded it can be fairly easily moved around. Keep in mind that some of the newer Bowflexes inexplicably left out wheels in their designs!
Still love the feel-very rigorous. Sometimes the burn is markedly more intense than that obtained from weights. I consider it the equal of weights, which is why i use both a Bowflex and dumbbells. Something to consider-the addition of dumbbells allows you to combine the two forms of resistance while further increasing the exercise options. For example, you can do dumbbell flys on the Ultimate using the bench.
If you use it regularly if pays for itself in no time. Especially now with prices falling, i'd suggest laying out a few extra dollars for the Ultimate, though you can't go wrong with the Elite or Sport either.
No need for a spotter, thus you can push the envelope and work to failure without worry. Big advantage.
IMO only the Powertec WB-LS weight pulley system is comparable. At $700 or so plus the cost of weights the price is comparable to a used Ultimate; a couple of hundred dollars less than a new Ultimate. I'd strongly suggest trying both an Ultimate and Powertec out in person before buying to determine which you prefer. If the difference in cost between the two's an issue, compare the Powertec with either a used Ultimate or a mid-priced Bowflex Elite or Sport. The Ultimate has the edge in space requirement, has wheels and is foldable unlike the Powertec, and is lighter given that there are no weights involved.
The Ultimate's built like a piece of gym equipment. No complaints at all. Very solid, resistance is very smooth. The more recent mid-priced Bowflex offerings like the Sport, Elite and Xtreme are also well-made and solid. IMO this is in part a consequence of the problems associated with the initial Bowflex model, the Power Pro. The Power Pro also provides an excellent workout, but doesn't stack up to these newer-generation models re: durability and solidity.
For those of us who care, it's an innovative machine with a modernist design aesthetic that I love. Futuristic look backed up by performance.
It's a keeper. I've worked out with weights for years, and i'll never sell this Bowflex. While there will invariably be those stuck on free weights who will disparage the Bowflex as not being comparable, my experience is that these guys usually have never tried a Bowflex or just can't accept anything that's not free-weight based. Actually the feel's one of the best things about the Bowflex in general-consistent, rigorous tension that is actually smoother than free weight systems.