Spotmatics are great cameras, I just love them.
I have used it for all my life years (my fathe rhad one brand new in '73) so I guess that is why
I have used/owned some other M42 bodies, Fujicas, Yashicas, Vivitar but always come back to the solid and yet smooth Spotmatic.
I have currently several takumars (super and SMCs) in
50/1.4, Fantastic lens, with a nice OOFA and final feel

55/1.8, so sharp it hurts
28/3.5, Amazing lens, maybe a tad soft in the corners for some but good for me
135/3.5, Very good tele, sharp
17/4, the fisheye
and have also used the 200/4 which was unfortunately stolen and I think it made an awesome portrait lens, specially outdoors and wide open or at f/5.6
I have also Fujinon lenses and Sekor lenses (aka sears) are good buys great quality.
The Skor 135/2.8 is very nice, and produces lovely images
I have also many off-brand lenses that are good enough, from KMart, JC Penney, Soligor, Spiratone, etc.
Recently, the lens that was a pleasant surprise was a 35/2.8 Hanimex HMC I picked up at yard sale for cheap. Nice sharpenss and rendition of color, almost no flare