Im not sure where you are located, but if you are looking to rent that SRI WHDI I dont see it available anywhere in Los Angeles, so you may be looking to purchase or rent from an owner.
While the Teradek has its applicaitons, I have experienced delay in the past. Maybe newer models are better, but I quickly abandoned it.
The Paralinx is super simple to use and has been reliable on every occassion Ive used it.
I personally own the CamWave (CW-5HD), and while I am not 100% satisfied (occassional signal drops, bulky size) it does the trick. There is an updated CW-7HD which Im sure is better.
Boxx Meridian is pretty high end and Ive never heard a complaint.
Are you looking for HDMI or SDI transmission? Ultimately it doesnt matter too much, because there are converters for that sort of thing, but I like less knots in the rope.
The lack of support and available information on the SRI model concerns me enough to entertain other kinds of transmitters, but if you are able to sample it, then I wholeheartedly support that. If you have a good experience with it, then maybe its the right one for you.
Sorry I cant give you any specific information regarding the SRI. I personally place a lot of importance on available reviews, support, and hands-on experience.