Personally i hate racks. They are good for breeders but for just keeping 'pets', i hate them. You can't see the snakes(even with the ones with the tiny window in the side) and generally they are only about 6-8" high. No offense to breeders who use them, but i picture them as a prison complex. A bunch of little 36x18x6 tubs.
I personally prefer to give my snakes cages at least 3/4 their length with optimum being cages their full length so they can stretch out and actually wander around.
Plus remember, with racks, you are only using flexwatt so you have to have a room which is kept fairly warm around 78F. So you can either use an oil filled radiator on a Herpstat HP or keep your whole house warm. You wont be using an RHP in a rack system.
Also i personally think that if a snake sees you every day and can actually see action going on in the room, they become more used to it and 'social' for a lack of a better word. All my always position themselves to look out the sliding doors of their cages and at night, will usually sit at the door looking out or down or periscoping. Now this might be just my impression but its how i feel and all of my snakes are really really laid back and like i said above, i can just reach in and drag them out.
I will say, racks are easier to clean, simply because you take a tub out, dump it, spray it down with F10, wait 15 mins and hose it out but again, no lights, nothing to see and usually pretty small. I havent seen any 6x3x18 or 8x3x18 tubs for racks.
The closest you can come to racks with the full size caging in something like what i posted with the pics of my cages. i have an extra T10 i could have put on that 5 stack but as it is, i need a little step stool to reach Louies cage on top to clean the back of it lol.