Forum is intriguing to me also....
I've been a longtime Burton binding fan, but I've always been so-so on ankle strap comfort. I'm tempted to try the asym straps on the Custom Restricteds, but I've heard mixed things on those as well. And I'm feeling a little sketchy on the re:flex bases... I love the concept, but the base components (pads) felt flimsy and I'm unsure how they'd hold up over time.
That being said - I understand Forum is owned by Burton, I wonder how much of the components that I like are shared between them? At a glance at a local shop, the ratchets seem as nice as the Burton ratchets.
I have 2012 Burton Cartel restricted Re:flex, 2012 Malavita EST, 2012 Forum Shaka, and 2012 Forum Factions. The Factions have the cheapest retail of all the bindings (although I paid between 120-150 for all of them new) and they feel more solid than either Burton pair. When I say solid I mean build quality and materials. They are aluminum and plastic, unlike the completely plastic Burtons. I think the materials used on the Forum bindings will make them last longer. I also don't like the reflex base plate, it feels cheaper than Forum's Good Vibes disk.
I like Burton's Asymmetric strap on both the Restricted Cartel and the Malavita. The Shaka has this also and it is equally good. The bubbler strap on the Factions is actually really good too, especially for the bindings being a lower end of the price scale. I have some Union Atlas and Contact Pro too. I think they all have pretty good ankle straps. So you really can't lose with any of these.
I'll just share this too. The toe straps work on all six pairs of bindings I have, I think the Burton toe caps are amazing, the Forum toe caps work pretty well too, and the Unions work ok they may just take some adjusting depending on the kind of boot and the size of your foot.