I actually have 2 of these now. I do triathlons and getting out of the aero position to drink really slows me down since I have to reach down take a swig and put the water bottle back in the cage (either below or behind me). Now, all I have to do is tip the straw in my mouth and drink up. When the reservoir goes empty, I pull a water bottle out of one of the cages and use the quick fill top (the cut up neoprene cap). I find that by shoving the bottle's nozzle in there and squeezing the bottle about 4 times empties it completely into the reservoir. Great system. They also provide a yellow coiled up plastic thing that looks like a shower pouf sponge. This device you are supposed to stuff into the neck of the reservoir to prevent splashing of liquid out of the top. It actually works. Wash it out really well after use though.
The only real problem with the kit is that the soft clear flexible tubing really smells bad. It also makes whatever you are drinking taste like the tubing. Absolutely horrible. They need to change whatever material they use to make it into something completely different. I usually throw away the clear tubing and cut a piece of clear tubing from my old CamelBak system that had too much tubing. That clear tubing is smell and taste free (even when new). (update 7-9-2014 new CamelBak link the old product was discontinued) Pure Flow Replacement Tube by CamelBak
Also, just to make things clear, you have to buy the Profile Design Aero Drink Bracket to make this system work with whatever aerobar system you use since the width between the bars may vary.
Another issue is that the drink bottle takes up a large portion of space up front. If you have your cyclocomputer (speedo, GPS, etc) mounted in between the aerobars you will need to relocate it elsewhere.
Somehow, this item listed as a "toy" so ignore my star rating with regards to that.