Most racers I know train with power. I'm not the type of person who pours over data, but I think it's pretty important to have a way to gauge effort when on the trainer, and to have a specific effort you know you can push during a time trial regardless of conditions.
I wanted a power meter that was inexpensive and easy to move between my bikes. I looked at doing a Stages power meter, but it simply wouldn't work between all my bikes (especially because of the age difference and one being 10-speed and the other 11-speed). I thought about doing PowerTap pedals because they would be easy to swap, but I have Speedplays on my bikes and having to move everything over to Look-style pedals seems expensive and like a hassle, not to mention I went from Look-style pedals to Speedplays because I prefer Speedplays.
So I decided to go with the PowerTap G3 Hub on a new set of wheels. To swap between bikes I'd just have to change the cassette (something I used to do before every race to get my race wheels on), and I could use a set of deep carbon wheels for time trials.
$599.99 / 325g / Shimano/SRAM/Campy Compatible / Coin Cell Battery
Because I purchased these installed on new wheels (not PowerTap wheels), I can't say anything about the packaging.
What I CAN say is that I added a field for power on my Garmin, and then when I went for a spin in the parking lot the Garmin beeped with the notification "Power Found," in the same way it does for my speed/cadence sensor, and then ... well, it just started telling me how much power I was pushing.
Seriously, it was that simple and I haven't had any issues with connectivity, ever.
If you keep up with this blog, you know that freewheel sound is pretty important to me. I like how this hub sounds. It has a loud, pleasant mechanical clicking sound (video below). That said, I imagine if the rim was shallower it may not have the same acoustics.
I've raced on this hub through our early spring races, on a road race, a circuit race and two TTs, and it's never given me any issues. And that's all I really ask of a hub. Well, that and I ask it to sound awesome.
So, would I recommend these? Yes, I would. They are one of the most inexpensive options, getting it going was crazy easy, and they haven't given me any issues yet. From the research I've done it seems like there's no reason to expect that'll change in the coming years.