I learned to dive on an AT PAC back in the 70's. (One of the first "techy" rigs, although I learned to dive it in my basic class. It was never "sold" as a tech rig, although is was promoted as a more advanced type of system, requireing special training.
Does anyone remember their motto, "Dive with Your Brains, Not Your Back"?
I still have it and can still dive it, as everything works perfectly. Because of its age and the lack of replacement parts, I will not take in the water anywhere outside of our local lake.
It was not a simplistic rig, but with only one hose, nothing in front of the diver but straps, and a hollow backplate filled with shot, it was perfectly streamlined underwater and balanced both at the surface and underwater. I even had the futuristic fiberglass "clamshell" for it, but didn't like it and only made one dive with it installed. But, as for the basic BC, I really loved it.
It had problems, including some serious design flaws, like the routing of the inflator hose INSIDE the exhaust hose and the potential for corrosion in the marble and lead shot weight mix that could prevent jettisoning of the weights in an emergency (you learned to pull the pin and do the AT PAC "butt wriggle", which is probably NOT what you would have done in a real emergency).
I did not experience either of these problems, but I inspected the inflator hose and deliberately dumped the weights in a barrel a couple of times a year.
I did witness an inflator related accident, when an instructor's inflator hose burst and literally pinned him to the cavern roof at Jug Springs. Lacking any sort of quick dump, this accident would have been very serious in open water, since it "rushed" him to the roof. But in the cavern entrance, it was mainly an inconvenience.
I finally got rid of my AT PAC in 1990 when a dive boat operator tried to ban me from his boat in Destin because "those stupid old fashioned back floatation systems were too damned dangerous." I was already tired of the grief I took on a previous trip to Cozumel, so I bought a "new style" Sherwood Prototype BC called The Spirit.
I hated that little BC, but I made dives with it for 12 years and it held up well. There was no support in the back, much less a backplate and when my air got low, my tank and rig would float up and bump my head and irritate the hell out of me. It was unbalanced underwater and ill fitting and I finally bought something new.
A few weeks ago, I bought a new Ranger BC. It didn't have a solid backpack/plate, but it felt good when I tried it on. All the stitching looked first rate and the construction was definitely heavy duty. I made a lake dive with it yesterday and it felt and worked great.
Underwater balance was wonderful, topside balance will require some trim weight I think, but my overall weighting requirements were less because it trapped less air. I had no trouble keeping upright on the surface, unless I way overflated the bladder, which at 44lbs. of lift, represents a bit of overkill.
The Ranger "fit" me quite well and felt very secure. For me, the lack of bulging wraparound floatation made the pockets a non issue.
I would have preferred a "no pockets" rig, since I think pockets on BC's, especially in the inconvenient locations they are placed, are a bit gimmicky and impractical. I much prefer my old method of clipping a pocket bag to my waist and strapping the bottom of it to my thigh.
But my Ranger was fairly inexpensive and I couldn't justify going to their "Tech BC" for fewer pockets and an extra waist clip, but more money. Besides, when I bought it, I had never heard of this forum, nor had I heard of "DIR" or the new focus on simple backplate rigs. If I had, I might have looked more closely at that alternative.
Like someone else posted, I am not a tek diver, I am a rec diver. I purchased the Ranger because it suited the type of diving I do (open water, usually above 60 degrees in a skin or 6mm wetsuit, no deeper than 110', but often weighted with camera gear and other junk.)
I think I'll like it for that type of diving.
If I decide to go "tek", I will sign up for training, buy the recommended gear and go from there.