Speed decreases the Recuperation Time. You can reduce the Recuperation Time of any sword to zero with level 5 Sword Expertise. If you are learning that skill, then the Speed factor is irrelivent.
My choice would be with the Frost sword. Frost can make the game extremely easy and you will have no problems for the rest of the game. I bought a sword with Frost (3) and haven't died since. If you want a challenge, but still a good sword, take the second one.
