Tony Vargas
Legend
Not much variance, on that count, I'd think. The EL guidelines of 4e were quite straightforward, relatively dependable, and an exact-at-level encounter was a resource-ablating 'speed bump' (same intent as a single CR=Level encounter in 3e), that'd break deadly only towards the end of an unusually long day (8+ encounters in all likelihood). Lower ELs below level -1 or 2 rapidly became trivial, above level +4 or 5, TPK territory. It was very easy to color inside the lines. If you /always/ stuck to exactly EL=level, though, and didn't have quite long days, you'd get encounters that may have remained tactically engaging, but would have eventually felt like foregone conclusions without much drama, precisely because the guidelines did deliver fairly consistently.4e still remains as least lethal because I haven’t hardly played it so I’m relying on others’ feedback, which has been a lot of “you had to try hard to kill a PC in 4e”
Of course, I imagine opinions will vary
Conversely, you'd get more variation in difficulty (and more possibility of lethality) running exactly CR=level in 3e or as exactly as possible to the 5e 'budget' guidelines.