I recently replaced added a Bent Up Cycles Aero Bag to my Corsa, replacing the home made "speed" bag that I've used all Summer. Here is my review.
Pros: Capacity. While most mfgs love to list the capacity of their bags in Cubic Inches, that doesn't help unless you've measured everything. After yesterday's ride I emptied my AB and discovered what it will really hold.
Riding jacket
Arm and leg warmers
Skull Cap
Balaclava
Gloves and glove liners
Spare tire (650c Gatorskin)
Bicycle pump
CO2 pump and 2 cartridges
2 spare tubes
Tube patch kit
Tire levers
Tire boots
Small bicycle multi-tool
Rear derailleur cable (tandem length)
2 Cliff Bars
1 small rock ??
Wallet and Cell phone
Clearance. I tend to have my seat laid back, which is why I can't use any of the Bachhetta bags without rubbing the tire. I had plenty of clearance with the AB
Zippers. The AB has dual zippers, unlike other bags which only have one that must be run all the way to the front edge of the bag. I prefer that style.
Safety. The AB comes with a reflective strip around the bag, another good feature.
Removeable bags. The AB has an internal velcro strip and comes with two small zippered bags that can be used to hold tools, wallets, etc. for easy access.
Cons: No Mesh pocket. I use speedplay pedals, and every other bag I've tried has external mesh pockets that are perfect for storing cleat covers in, so you don't have to open the bag to get to them. Time to get out the sewing kit.
No hose feed through. For those who prefer bladders instead of bottles, you would have to leave the zippers open a little to let the hose out. I am one of those who prefers the bladders so I can drink while descending.
The Jury is still out on: Side bottle pockets. The main feature of the AB is the two side pockets for holding bottles. Due to the location of my light bar I cannot place the bottles into them while riding, so I am not sure how useful they are without seat mounted bottle holders as well. Having the ability to carry four bottles is good, I'd just have to stop and swap at some point. Those pockets could be used with a bottle sized tool pouch.
Overall construction. The AB looks good out of the box, let's see how it looks after a full riding season.
Cost. It is a bit pricey ($139 plus shipping), but it let's me carry what I need for the winter season without having to change my seat position, so for me it is worth it.