Shamino figured out the gear game a long time ago and may have even been in the watch making business. Look at cyclist. The vast majority run Shamino gears. Maybe started in the watch business then got into other areas. I was a revo kind of guy but now run Shamino. Not going to lie I went to the top with Shamino so I should be very happy with their product and I am.
Never in the watch business, but you are right, Shimano has been making bicycle gears since 1921.
In terms of 70 vs. 200 size. The number is an indication of line capacity.
The 70 size has an updated version of the SVS Infinity braking system that requires less frequent maintenance than the original braking system in the 200 size.
Line capacity:
70 size: 85 yards of 12 lb
200 size: 110 yards of 14lb
I use my 70s for flipping, pitching, roll casting, short distance techniques with up to 20lb test. I also have one that is spooled with 10 lb for throwing a variety of smaller and lighter weight lures. The 70s are much more compact than the 200 and weigh almost an ounce less.
I use my 200s for basically everything else. Any full cast technique where I am using 12-20lb test. The noise issue that some people are having can be eliminated by wiping off the brass colored brake ring and applying a light coat of oil to it. I find myself doing it every few months or so. With the 70, I have yet to apply oil in ~6 months of use and am not hearing the brakes working like I do in my 200s.
I have 2.5 years of heavy use on my 200s and all of them are still smooth and cast really well. I sold off all my E series reels except for 1 I have sitting in my parents garage.
This is the ring that requires occasional lubrication to prevent brake sound (side plate is attached with a bar on the 200, not attached on the 70)