I don't install so this is question from inexperience but I have heard that 6a is a lot more bulky, much larger minimum bend radius and very difficult to use in compact camera housings. Any experience with that?
In my experience 6A is bulky, difficult to pull, and harder to terminate. Also, when it first came out there was alot of talk about ANEXT and therefore we used shielded, which added more complexity. I'm not one to shy away from difficult work, but considering that the majority of our projects have average data runs of 200' or we are getting 10Gb performance from enhanced Cat6, so I really don't see the point. I haven't used it about a year, so forgive me if something's changed in that time.
Maybe customers like to see CAT6 in the proposal but it's not necessary and you aren't future proofing yourself for anything. With more advanced codecs I doubt in my lifetime we will ever approach or even need to approach the limitation of a CAT5E cable. It's not like you can go further with CAT6. The cable certifier will fail it just the same. If it makes the customer warm and fuzzy leave it in the quote but otherwise why bother?
I use Cat 5e whenever possible. The pros are numerous and I can't see any cons. Some talk about "Future proofing" but we are going toward better compression schemes ( see H265+ and similar) not the other way. For where we see bandwidth of the cameras we use, going ( mainly Hik and Axis) one could well use Cat 3 :p. I am also yet to see a current model camera pushing above 50 Mb/s, let alone 100 Mb/s... Would like to see tests of a camera pushing 1000 Mb/s which Cat 5e can handle BTW. On the power side Cat 5e can go as high as 50 watts... On top of that, there is no doubt Cat6 can be difficult to pull at times .. with all these, we frankly can't justify the price differential.
Some customers like to see "Cat 6" on the specs sheets ... then we use these, else, Cat 5e all the way.
Generally I'll pull Cat 5e for most of my camera systems. If someone request CAT 6 of course I'll run it but on some of my bigger projects I will always go CAT 6 because it's a little bulkier. I find CAT 6 just as easy to run as CAT5e. I take pride in my terminations and I love terminating CAT 6 sheilded or not... also not all CAT 6 has the plastic spine. My product dealer sells me Honeywell CAT 6 wire with spine or without. Outside of camera systems if I'm building a hardwired structured network for someone I'm going CAT 6 all the way. Also if I'm incorporating access points or bridges I might go shielded just to meet product specifications or recommendations or just to secure the warranty on the device.
CAT 5e awesome and cheap but I fell in love with CAT 6 the first time I messed with it because the copper is bulkier and the wire feels that way too and price is really not bad.