IMO - The Tamiya tracks in the Marder III kit are poorly detailed and any OOB Marder III I've seen looks unconvincing, largely due to the tracks - even if the modeller makes the effort to tie them down. I'm also known as being pretty anal about these things though. You have to put in enough extra time working the indy tracks (albeit rewarding work) it's almost like working another kit any way - the results are outstanding and you end up getting your money's worth (IMO).
If you want another alternative to one piece tracks, the resin tracks from Accurate Armor are much nicer than the Tamiya vinyl tracks, and there are longer sections (about 8 I think). But, you have to heat and form them around wheels.