Although the late Stephen A. Camp was known as an aficionado of the Browning Hi Power, as an LEO handgun instructor he learned to master Glocks and other pistols. He wrote two articles on the 17L, and they were what made me jump at the chance to get mine some years ago. He preferred the 17L to the 34.
I like the way my early 17L handles and points. Because I seldom get to a range, I do a lot of dry firing, and the trigger is now very smooth. The gun did need a little skateboard tape for its Gen 1 grip. I've handled the 34 and I think I would be happy with it if buying new. Holsters are indeed, harder to find. I have two: a Hogue Powerspeed Retention and a Safariland GLS (Grip Locking System). Both work just fine.
Just me, but I have no problem with not being able to mount a light or optical sight.
I guess it's because I used to be a revolver guy, but I find the comments about the length of the gun a little amusing. For me, it points like a revolver. Its overall length is only a fraction of an inch over that of most current four-inch barreled wheelguns. As I get older, I appreciate the lighter weight, the longer sight radius (eye fixed with cataract surgery!), and the easy racking. Less noise and fuss. Someone recently posted 17L chrono results with the military's new M1152 load and got 1370-something with its 115 gr. flat-point FMJ. I've shot some Underwood +p (not the hotter stuff), 124-gr. and it was ridiculously easy to shoot. While I am realistic about how long this old decrepit guy would last, I find the thought experiment of a TEOTWAWKI one-gun interesting. The 17L would beat out my lovely old Browning High Power when the zombie hoards came over the hill!
You can't go wrong with either the 34 or the 17L, in my opinion.
P.S. I'm very glad someone has kept Stephen's site up, and I believe his books can still be purchased. He was a real gentleman of gun writers. Here's a link to the first of the 17L articles: