Re: A few maybe not so simple questions ?!?
1) IMO Al Fahker is much better than Layalina. As for Starbuzz I have only tried 3 flavors and only liked 1 out of 3.
2) Nammor and Razan hoses are wider and therefore offer a draw that requires less effort. Usually less resistance means a bigger hit.
3) The design of a funnel is to catch the juice instead of letting it leak down the stem into your hookah. More juice kept in the bowl means more flavor and longer sessions in general.
4) Exoticas are great coals. I have never had a problem with them. I have heard Al-Ajdad are not that good. Exoticas have outscored them in nearly every review.
I haven't used a Heba diffuser, but I use a homemade diffuser and IMO it works well.