I think the thing to remember with picking a track to use on your layout is it solely comes down to YOUR preference.
No one here can tell you what to buy so I generally would suggest trying out both and comparing their performance. I do think it is strange how Realtrak segments do not align well but as others have said the solid rail feature is really a big plus. So, like I said, it solely comes down to performance and maybe your aesthetic tastes.
As for me, I have used both and found Fastrack to be much more reliable even though it is noisey on certain surfaces. Additionally, Fastrack looks, to my eyes, more realistic than Realtraks even though both are not perfectly prototypical.
