I have a pair of their entry level shoe the A-Three.
I did try Shimanos on (R87 and R133 I think) as I hadn’t planned on spending that much, the Shimano shoe tapered a little bit more towards the end while the Bont is a wider fit.
I did oven them as their instructions tell you to do on the website, it seemed to make a small difference.
Anyway, once on I don’t notice them at all which is what you want. May just be my feet, but I do the ratchet mechanism up and then the velcro straps are almost surplus to requirements, they don’t add any extra tension onto the top of the shoe.