I owned both the SF1 and SF1n in the late 1980's. Far from looking "clunky", they had a very much modern look to them. The controls were very clean, and it took very little reading of the owner's manuals to be proficient out of the box.
The auto focus systems were very advanced, and in fact, were superior to similar Nikon models. Nikon only had the N4004 and N6006 at the time, and the Pentax was miles ahead of them. I bought mine with a couple of Pentax A/F zooms, and added from there. While primitive by today's standards, they brought me a slew of good photographs. As time passed, and the SF1's technology started to seem "old", I traded for the PZ1, both the PZ1 and PZ1n.
The attached photo is the very first I took with the SF1 (35-70mm A/F Pentax). A couple of miles from my home I saw a huge smoke plume which turned out to be a fire at a scrap tire yard. I got there in time to follow the firemen into the area. At the bottom of the photo is a tangle foot of steel belts. I liked the image, and worked with a couple of labs for a good print. This spring I finally scanned the negative, and cropped to fit a 8.5x10 print. No other edits were needed. Titled "Into The Smoke".