I had Pentaxes, and still have one I gave to my wife because it is small, light, and has a very bright viewfinder (ME-Super). As for me, I cannot concieve a SLR without a matching needles system, and in Pentax there are few choices and some very expensive or rare. So I went to Ricoh, I also could buy here in Canada under the name of Sears (which saved me 100$ for the pro XR-2s rebranded).
What can give you a Pentax K1000 that its equivalent, the Ricoh KR-5 super (or A-50 super) cannot give? Yes, the speeds 1/4, and 1/2, as the KR-5 super stops at 1/8. But what it brings that Pentax doesnt, are: a selftimer, mirror lock-up (when using the selftimer, like with ALL Ricohs), a vertical metal courtain, and as result a X-synchro speed of 1/125, and I'm sure I've forgot other 2-3 features. Oh, but Ricoh has the uper and the bottom leads in plastic... Yes, so what? There are simple leads, and their plastic isn't more fragile than Pentaxes fine metal leads. As for the chasis, Ricoh's always metal ones are build like tanks (in part if not more rought than Pentax).
And you have choices: You want a total mechanical pro body, matching needles style, go for the Ricoh XR-1/XR-1s (the "s" means hot shue, if I recall). You want a pro body with aperture pryority, go for the XR-2/Xr-2s (with metal needles) or for the XR-7 (with LCD needles). You want a basic matching needle body, like the Pentax K1000, go for the KR-5 super ("super" is important, because the earlier KR-5 doesn't goes shorter than 1/500). And if you want to save money, buy the Sears branded equivalents - see Butkus page for K-mount bodies other than Pentax (it is the no. 1 resource):
http://www.butkus.org/chinon/index.html
And I forgot: besides the mirror lock-up feature all Ricohs have when using the selftimer, the bodies with electronic shooters have
continuous shooting speeds, which means it does not jump, let say, from 1/125 directly to 1/250 or 1/60 by the smalest light variation! Does afordable Pentaxes do so? My wife's ME-Super doesn't! And like with electronic Pentaxes, Ricohs have a mechanical shooter speed for the X-synchro, in case the batteries leave you (mines keep already since 5 years, and still work, and I've shoot all this time about 50 rols per year per camera).
Finally, if you want a really cheap Ricoh, buy it "defective": with the mirror friesed in upper position. Almost no seller on eBay knows that when electronic Ricohs have no batteries anymore, the mirror locks-up. They think it is defective and sell it for nothing. All you have to do is to change the speed to the X-synchro or to B (both mechanical), and the mirror will come down. Put new batteries and all will work like new.
Really, Pentax always takes your money for every single feature it ads, while Ricoh gives you twice as much for nothing.
As for Vivitar/Cosina, they are great cameras, but with the 3-LED system, I don't recommend. Chinon might be a viable alternative, but I don't know much about. Look on Butkus' site.
Good luck!
