I bought these shoes to replace a pair of Sidi's that finally wore out after more than 12 years of riding. I have wide feet and the Mega style fit well. I wear size 10.5 street shoes and I ordered size 45 Sidis. I was not familiar with the fastening system that Sidi uses, which they call Techno 3, but after careful reading of the instructions I find it easy to use. These shoes are very well made and I expect them to last like the last pair.
I wear a size 15 shoe, and the Sidi Alba 2 Mega are a perfect fit. This is the first cycling shoe I've had that was wearable out of the box. Comfortable on long rides. These are a bit more expensive than some other options, but it isn't worth it to skimp on specialty shoes.
These Mega shoes are the bomb for us old guys! My feet have flattened and spread. Had to let my two other pairs go;sadness. Can't say enough about these shoes. I did switch out the foot bed though. I have happy feet now!
Road shoes that I has bought originally in regular, but had to buy again in MEGA width size. Super stiff and that sometimes causes a bit of numbness, but otherwise comfy. The dial is a bit funky to adjust on the bike, but not impossible. They also looked like they weren't vented very much, but they do seem to get air flow to the feet.