I actually talked to Matt from RadioPopper yesterday evening on this very subject. TriCoast also tested the JR's out (you can see what we did with them
HERE blending eTTL and Manual Alien Bee's together with completely control for the first time ever)
At LightPro two weeks ago we also used them and they worked perfect.
To my knowledge they are getting all the plastics formed and ready to go so that usually is the last step in getting them on the market.
I know the RadioPopper people have the electronic boards, packaging and other items already at their office so as soon as the plastics are done (as mentioned the redesigned switches delayed the release) they will be out on the market.
My guess would be by the end of May these guys will be selling.
I know from what I have tested these guys on already - I will be converting our studio to them and leaving the Pocket Wizards to collect dust or hit Ebay. Now with this system I can do everything a PocketWizard can do AND MORE since I can control my Alien Bee's. I am looking forward to controlling my mounted hairlight in the studio without any wires or ladders to adjust the power and outside with the Vagabond and AB1600 shooting seniors in the backyard of the studio.
No more than 6 weeks would be my guess (on the long side of things) and these guys will be out.
As Brad said the PX is the TTL version and the JR are the dummy triggering device with two models - one to just trigger (as a Pocket Wizard) and one to trigger AND control your Alien Bee Units.
So for around a $100 you get a VERY secure and reliable trigger unit where Pocket Wizards doing the same thing on a Radio Freq. not nearly as secure here in the U.S. costs around 3 times more. Does not take much to figure out which one I want to use in my business. For YEARS Pocket Wizard has made a so much money on a product that really is not that special, it is about time someone not only gave us photographers a product to compare with Pocket Wizards AND as it seems actually out preforms it now on just about every level their product preforms at. I can get more equipment for the same money using the Radio Popper system AND have that equipment work better and blend into a "Family" of wireless systems which preform better than anything else on the market. Simply stated it is the strongest "system" for both studio and outdoor wireless flash shooters.
Also the PX Transmitter CAN control the JR receivers as well which is what we did our in testing, but the JR CAN NOT control the PX Units.