The article Jim is referring to is really useful, it compares 4 manufacturers 251 tracks and compares them for scale size etc. I used some 251 Fruil's on the 251c that Dragon issued, and although they looked nice, once painted, the difference between them and the kit indy links is almost impossiblt to see. The AFV ones are nice, I used a set on a sd.Kfz 11. The dragon EZ tracks are I believe, late pattern, but are a B****** to fit together, whilst the normal indy links that come with the Dragon 251 kits are not as fiddly and look great when finished.
In future, when I'm doing another Dragon 251 kit, not worth buying Fruil. To much trouble buying AFV. Too fiddly to fit Dragon EZ, too fragile using Modelkasten....I'm sticking with the kit tracks!
Vinnie