It has the same shutter as the F. All my Fs needed calibration, and that is expected. Nikon F guru Sover Womg mentions that in their day, pros would have their Nikons serviced/calibrated once a year.
The only shutters that really stay in tune are electronic metal bladed ones.
Funny, I have several F cameras, from the 640 series to the Apollos, none has ever required a shutter calibration, ever. Most have never had any service since new. I have a Kyoritsu shutter tester, and used it to check my F cameras (I have 9 right now), all are within spec. One of my friends here was press photographer who shot photos in Vietnam and the middle east wars. He said that he never sent any of his three Nikon cameras in for service. I cleaned them up a last year, and replaced the rotted rubber seals. The shutter speeds on all three cameras were still within spec.
S2 cameras do not have the same shutter as the F, which it titanium, the mechsnisms are also slightly different. The S2 uses a silk shutter, which is quite durable. However, the shutter curtain ribbons can fail in the older S and S2 cameras. I have found it easier to replace the ribbons in old Nikons than the ribbons in FSU and Barnack Leicas. The S3, S4, and SP have the same shutter mechanism as the F (though not all have titanium shutters), and even have the same shutter speed dial.
I have shot pretty much every "Pro" system, from the Canon F1, to the Pentax LX, to the POS Minolta X1, to numerous Leica M cameras, none are as durable as the old Nikons. Two cameras I will never sell are my first black paint F, and my F2 Titan. I know that these cameras will always work, no matter what.
The best S2 is the black dial variation, the best lens will be a black 5cm f/1.4. The other lenses will require an accessory finder. If you shop around, you can get an S3 which has built in frame lines for the 35mm lens, the S2 is better as a 50mm lens camera. I have both, and enjoy them equally, though I love to shoot the Nikkor 2.8/3.5 with my SP, which has a built in finder for wider lenses.