Thanks to everybody for your help.

Do your refills work better when you hold the pen more
vertically?

They do, but this is a very different style of writing for me. I
learned to write in Russia, and sometimes I think that my way of
holding a pen is different from how most people do it in other
countries.

Have you tried the Parker fine?

Not yet, but I'll keep this in mind.

Since pens are so subjective, I suggest that you find a refill you like,
first, then look for the pen that it will fit into.

Good idea.

Is there a way for you to tell if you got an old one or a new one? Did you keep the blister card in which the refill was sold?

No, I don't have the blister. The first refill came with the pen, and
I wrote a complaint about it directly to Sanford. They were nice
enough to send me another refill free of charge (also without the
blister), but it was not much better.

Evgeny