What are some great brands/products for cages both behind the saddle and between aerobars with a straw?
Specialized makes a nice one for behind the seat. They actually hold the bottles in when you hit a bump.
Jim
behind bottles, there is no better cage than the arundel mandible. It WILL NOT eject a bottle. Trust me, I tried really hard to make it do so, and the bottles never budged.
arundel mandible for behind the seat- light and strong. not cheap, though- but worth every penny.
Thanks! It looks great. I’m curious how I would get an accessories back to fit below it, though??
For between the aerobars most cages will work (since the bottle is lying flat). Just make sure the cage has the “hook” that fits in the neck of the bottle, so the bottle cannot easily slide out, and you know when it’s seated.
I’ve been really happy with the arundel sport cage for behind the saddle, but its just plastic not carbon, so its not ST approved. 
Bontragers rear mount is great, have used it all year, 0 bottles ejected on chip sealed roads, RR crossings and such. It come with cages that face the rider which aids in the non-launching sucess I have had as well as buddies that use it. But the big plus was its cheaper by far.
DIY, I used a old carbon fork steer tube cut in half,zip ties for the front and rear bottle.
I have a home made copy (very nicely done I must say) of an original Minoura double behind the seat holder. It mounts on the seat rails so no worries with aero seat posts. The original ones were folded sheet metal, not the bent rod like the newer ones. My first one rusted out after too long ridnig in salt spray from the sea. I made mine out of stainless steel sheet and it has worked a treat, BOMBPROOF. The only bottle I have lost in 17 years of using the original and my replacement, was when the bottle cage attaching to my new one, broke, and the bottle, complete with cage still attached hit the road. I currently use cheap Elite cages, but have been looking for a pair of Blackburn stainless steel bottle cages, to match my SS one on the seat tube.
On my home made Minoura one, I have two bottles, with my CO2 inflater between them and in the U of the bottle holder do-hicky, I have a small pouch of spares hidden behind/under the seat. Very sweet setup I have to say, and did I mention BOMBPROOF!!
For between the aerobars, I have about a 14 year old Jetstream, series 2. Series 1 was round like a normal bottle. Mine is oval and can work in both directions so the straw location can be moved forward or back to suit your face or preferences. The series 3 was more tapered still, but wasn’t symmetrical from the side, so could really only be mounted one way. I have had no need to replace mine, it still works perfectly and the new ones are stupid expensive and don’t seem to work as well as the one I have. Don’t fix it if it ain’t broke. 
found this on Ebay
http://cgi.ebay.com.au/...d0fd3#ht_3983wt_1137]
That looks NASTY! Cable ties? Seriously?
OK, so it’s carbon so all sorts of people will buy it, it must wobble around like crazy. I’ll stick with what I have already thanks. Aw hell, I’ll bid $1, but that has to include shipping! LOL. surely I could find a use for a flat piece of carbon like that
Between aero bars with a straw: Profile Design. This being said, I bought one but once properly fitted, the straw was too far back and annoying, and also the PD bottle doesn’t let you just swap bottles on the course, so I went with a rocket mount, home made with zip ties: http://frenchmans-tribulations.blogspot.com/2010/08/rocket-bottle-mount_23.html
Edit: a couple pics from that blog entry:
Cost is four zip ties (and three plastic grommets because I was anal about it), and a tiny bit of time with a drill to make holes in my case, though you do not even have to make holes depending on the cage.
For behind the saddle, I went down tube…
What is Chris Leito and some of the other pros using. Looks like theirs is put together with a more stable system. Certainly there is a bottle cage product out there that works for a single seat rear mount.
Chris uses a proprietary front stem mounted holder for his speed bottle, and simply cable ties to attach an under the saddle cage. I have found the Bontrager cages to be both inexpensive and extremely good in holding bottles.