As long as they send you the one for Samsung you should be OK with the Pentax.
I love my Metzs but I'm biased. I have a 58 AF-2 for my Pentax and a 58-AF1 for my Nikon. I also have several of their older handle flashes or potato masher types which work fine although they're about 20-25 years old. What impresses me is that you can STILL purchase battery holders for their 25 year old flash units.
I like the Metz company, I had several questions and I emailed them directly in Germany. Generally within 24 hours I get a reply from their tech support guy.
The front little flash on the unit is mostly to put a catch-light in the eyes, it's only adjustable for 3 power levels. The menu system they use does take a bit of getting used to but the flash is very capable and can do stroboscopic flashing if you want to.
Being able to upgrade the firmware yourself is great. I've upgraded both mine and it was one of the easiest things I've ever had to do. I would suggest though that you download the manual from Metz and study it before you bid or buy it though.
Home: Metz generally takes you to their english site.
Hope this helps.
Michael