Get a quote from Mark. I suspect a CLA from him is going to be less than $100 and a Yashicamat is a great camera.
You might opt to buy another working one on ebay for less money, however, most of the Yashicas going at this price need a CLA anyway, or will do within a short time of buying them.
The simple problem is 40-50ish years of gravity, dragging the grease into places it shouldn't be, added to several years of drying out of said grease into stiff gunk.
Rolleis are great cameras too. Your budget will dictate what to get, but old cameras almost always need some attention if they are going to be used.
I got a quote from Mark Hama a while back for a CLA on a 'mat 124 (can't remember if "G" or not). As I recall, it was significantly more than $100. That said, he doesn't just fix 1 thing, he goes over the whole camera.
"Far more critical than what we know or do not know is what we do not want to know." - Eric Hoffer
Funny, my beater Yashicamat with the Lumaxar keeps going, although it can seem like it's jammed every once in a while. Try turning the crank backwards a bit, then back forward, then mash the shutter button kinda hard (but without forcing any part of this). That always does it for me. I have a Rolleicord that has a sticky shutter (every speed is about 15 seconds) but the Yashicamat takes such good pics I'm not in a hurry to fix it.
A hundred dollar CLA on a Rollei is a far better investment than the same CLA on a Yashica.
That's true Jim as a proportion of the value, but how much would it cost him to buy a Rollei ?, and if he buys another Yashica TLR who knows what other faults it may have, because very few of these cameras have ever had any maintenance in over twenty years since they were manufactured.
If you are going to use it, I'd vote yes. As to the Rollei vs Yashica comparisons I'd say it is meritless as buying any used Rolleiflex today unless it has been gone through will be in the age range where it should be gone through. The Yashica is a good user and until you've moved beyond its capabilities I'd not fret. I used a MatG for a few years and an earlier version, can not remember the model and other than I happened to fall into a Rolleiflex Automat and a T, I'd be using it just as happily as when I owned it not the Rollei.