I have been using a Galco Miami Classic shoulder rig for awhile now and really like it. The narrow straps of the harness allow my sking to brethe bettern than some of the rigs with the wide straps. The leather work is what you would expect from Galco and the lead time is only about 5 days from online order to receipt of the holster. The holster is really stiff when it's new and has to be borken in like a baseball glove by massaging it until it becomes more pliable. My Walther wouldn't even go halfway in util I sat down and worked the leather for about 45 minutes, then it slid in and out just fine. The cot about $200 with the double mag pouch and the tie downs (the mag pouch comes with the rig, the tie downs are seperate), not cheap but you are definately getting a quality holster.

Here are some pros and cons that I borrowed form the web:
Advantages of the Miami Classic:

Pretend you're Sonny Crockett;
Take a dump in a public restroom without removing your gun;
Carry 37 rounds of +p 9mm;
Pants don't fall down;
Gun doesn't peek out from under your jacket;
Excellent retention;
Easy draw while seated in a car;
Comfort, especially if your work involves driving, flying or being seated for a long time;
Easy to put on and take off;
And you can pretend you're Sonny Crockett.
Disadvantages:

The draw is slower;
You have to leave your jacket on;
You have to endure jokes from your teenage offspring about Sonny Crockett.

Back in the late 80's, Miami Vice used to be my favorite show ... used to love Sonny's Bren Ten ... anyone remember that gun? Wasn't it the first production 10 mm? That's before the .40 was invented.

I never tried shoulder carry ... I have a friend who only carries that way, though he only carries "when he thinks he needs it" The "bra strap" printing doesn't seem to be too bad.

It is a whole lot more comfortable driving with a shoulder rig. It is also easier to draw your pistol while seated in a car when you have a shoulder rig. I accumulate a lot of windshield time each week so I prefer a shoulder rig. The downfall is you have to wear a jacket or long flannel shirt to conceal it.

What's the scoop with the tie-downs? Are they necessary? I'm planning on getting either SSII or Miami classic and I hate to spend the money on the tie downs if they're not all that necessary, but it does seem like it would constrain the swinging.

I wish they made their vertical system for a larger number of guns, or at least the guns I want to carry with it.

Dornaus & Dixon basically had Norma design the 10mm auto cartridge for their Bren 10. I don't remember what other makers adopted it after that, but for sure Colt and S&W did. S&W designed their 10mm series of pistols around a contract for the FBI who were shopping for something with more stopping power.

The as-designed 10mm turned out to be more than many FBI agents could handle and they requested S&W download it to what's known as "10 lite" or "FBI loads".

S&W figured out that they could cut the case down and still keep 10 lite power and make it work on the smaller 9mm-sized frames. Thus was born the .40S&W cartridge.

The S&W 10mm pistols are some of my favorites, although I was lusting after a Kimber target in 10mm today. It's too bad you have to buy them with money and not with love, or it would have come home with me.

They may be necessary for some people and not for others. If you don't carry two full mags then you are probably going to want to tie down the mag side of the harness or your handgun is going to droop down to your waist and your mag pouches are going to be up in your armpit.. I use tie downs on both sides to keep my gun and mag pouches from flopping around when I am bending and doing active things.

On my bodyguard, it only came with one tie-down (magpouch side) and I found it most uncomfortable. I am 6-4, and it just wasn't long enough. I know what you're taling about with the swinging gun, but I think it reduces the printing of the muzzle when you bend over. Two 1911 magazines make my all-steel 5" comfortably balanced, albeit not perfectly balanced. Two double-stack mags for ballast just might be downright exquisite!!

I took off my gun side tiedown yesterday and just used the mag side to try it out that way. I was suprised that the gun didn't flop around too much at all other than the butt trying to poke out from under my shirt when I len forward. If you are 6'4" you might want to think about getting tiedown extensions if you think they would be useful. I am only 5'10" so they work perfectly for me and make things stay put.