Most of the discussions on adjustables tend to settle on one of three:
Powerblocks: My own personal favorite. Some of the models are priced at a higher premium than other brands, but the build quality is indisputable. Many models are highly upgradeable (with some variants permitting 115 lbs+ per dumbbell once upgraded). Adjustment weights are worse than for Selecttechs, but better than Ironmasters.
Bowflex Selecttech: Seems to be fairly popular in the TBB community, likely as a result of their promotion with P90X+. Probably the 'fastest' adjustable available, although I've always found them to be a bit unwieldy; they have a larger footprint than Powerblocks or Ironmasters.
Ironmaster: Excellent build quality with the most traditional dumbbell feel of any adjustable, although adjusting the weights is probably the most time-consuming of all adjustables.
Whenever someone asks for a recommendation, I usually recommend that they check out a Dick's sporting goods, or some other outlet which carries the brands in store. There are just too many subjective variables to really be able to qualify one brand as being clearly 'better' than another from any objective standpoint.
As an fyi: if anyone has the space, investing in dumbbells doesn't need to be as cost-prohibitive as you'd imagine, as there is a sizeable market for used/secondhand weights that can offer substantial savings.
iamkuljuarenot:
I use the Powerblocks and pretty much the only time I get left behind is on drop sets and some progressive sets. Other than that it is pretty smooth, if you have to pause it for 5 or 10 seconds to switch weights, big deal. Once you go through the workouts a few times and know what's coming you will have less need to pause the video.
Same here - I've got the (Stage 3 upgraded) U-90's. Definitely a bit of a challenge keeping pace with some of the supersets and progressives, but that's true for any adjustable.