AFAIK the correct designation for this pistol should be
28PK rather than the PK-28, but I could be mistaken.
I don't own one personally, but the 28/30/31 series Stars are considered the equivalents of a Beretta 92, S&W Model 5903/5906, or SIG P229- built like tanks, reliable as the sunrise, but large and heavy compared to newer tactical plastic of equal capacity. The "K" suffix indicates an aluminum alloy frame, so it's not quite
as much of a boat anchor as a standard 28, but it's still not exactly svelte.
Like the other pistols I named, it has been criticized for a somewhat large and blocky grip shape that's not friendly to those with small hands. The "P" suffix stands for "Police" and indicates a slightly shorter barrel and slide, but IIRC the difference is only about 1/2", so it's better characterized as "less long" rather than "short".
One potential issue is that the 28 supposedly uses a different extractor design than the later 30 & 31 series, but the 28 was not produced for very long before it was replaced by the 30, so replacement parts may be an issue. IMHO the extractor on this pistol should be carefully inspected before purchase.
One other potential issue is that the 28/30 series have a peculiar safety mechanism- the safety does NOT decock the hammer, but the hammer will drop against the engaged safety when the trigger is pulled. I consider this a BIG NO-NO on a defensive pistol because a shooter could potentially mistake a safety-on hammer drop for a FTF and waste valuable seconds clearing a perfectly good live round, only to have it happen again.
I greatly prefer a traditional safety mechanism that either locks the trigger solid or disengages it so the shooter will get instant tactile feedback that the safety is on. OTOH if the pistol will serve only as a range toy, this may not be a big deal.
Personally, if it's a good deal, I would buy it anyway- who knows when you might see another one?