I like the decimal / fractional UE.
It emphasizes every single UE spent, even fractions of UE. It does that by implicitly conveying the fact that the game engine is really 'splitting hairs' when it comes down to skill checks, and every single of IOTA of UE spent on a skill or attribute is being factored into the skill checks.
The only pet peeve I have with the system, and it isn't even a major peeve, is when assigning UE to languages. If you have (for example) 0.1405 UE left to assign, you can't assign all of it. You most you can assign is 0.1404. It's not a major issue, but the interface is worded that you "have" a certain amount of UE to assign, but you cannot technically assign (all of) it.