Despite the naysayers it has its bebefits. Given that you are willing to use good form it will give good resistance and work stabalizers much better than other machines. Certainly free wieghts are fantastic, but they can be a problem if one wants to work out alone in solitude. The machine really shines if you also have access to other equipments that you can use as the weight limitations of the Bowflex hinder anyone with significant strength for doing squats; and obviousloy deadlifts are a no go.
Pros: Safe to work out alone'
Good resistance for all but the strongest muscle groups.
Might find using it fun ( I sure do)
Can do traditional cable excercises.
Models with a bench, Doubles as a bench for barbell excercises.
Good customer service, and the manual that comes with it is A+
Cons: They are expensive
No squats or Deadlifts which are sacred of many here
"Guarentee" they give is BS as it will still cost you 400 in shipping
Not as primal and manly as freeweights (sounds silly but it matters)
Still need access to a bar and/or dumbells if you want a true total body workout.