In Finland, Nedomansky seems to be somewhat more legendary player than Martinec, for whatever reason. Maybe we like goal-scorers more (the one area where Nedo definitely has an edge IMO) or maybe it is Nedomansky's much more impressive physical appearence; about 6'2 to Martinec's 5'9. Nedomansky's GPG numbers are more impressive - both in the Czechoslovak league and internationally - but if all the assists were available (are they?), it (PPGA) would be a lot closer, I think.
I'm not sure how much credit we should give to Nedomansky for his North American career. He had a good longevity but didn't seem to have any true super seasons, not even in the WHA (or 1975-76 maybe?). Martinec took a more 'easy way out' and spent the twilight of his career in Germany.
I have seen Martinec play much more, so I can only really talk about his "package" (no pun intented!). I feel safe to say that he wasn't one-dimensional at all: above average defensively, dangerous forechecker, not maybe physical à la Mikhailov, but wasn't bothered by physical play either (many good performances against top Canadian teams).
By the way, an interesting thing is that Nedomansky, like Jiri Holik, was basically a non-scorer against the Soviets until 1968, but after that he was very effective. Can't help wondering about the impact of the 1968 invasion had especially on the CSSR players; most notably in the 1969 WC, but later on too. Czechoslovakia had skill, but I think it's safe to say their success versus USSR was even more about the will.