My personal advice is try to obtain a tube of Superlube at your nearest hardware store (Lowe's, Ace, Home Depot should all carry it, although just call in for availability) and lube the stabs. Lube around the plungers, as well as where the metal bar contacts the plungers on the bottom. This will take some maneuvering, and a toothpick works well. Use very sparingly, and let that set in as well. Should feel a little better, especially for the space bar.
I own a Ducky Shine, only a few months old, but after a little typing and breaking in it should feel a lot better.