On the Pre/Post Edge question, there's an extra mechanic involved in Anarchy that makes a small difference:

Many Amps (the generic term for almost anything that gives your character a benefit such as spells, cyberware, etc) can do things like grant you a re-roll of a failed die when making a test. Presumably this would be applied to failures after a pre-Edge, still allowing 4-5-6 to be hits, but before a post-Edge re-roll. A fellow runner did the math, and in this situation the math comes out a little better to pre-edge if you only have a few dice.

However, that still probably doesn't outweigh the benefit you get with post-edge of waiting to see if you need to use the Edge or not (as you mentioned).

But as this friend pointed out to me, if I'm focusing that much on the math, I'm missing what Anarchy is really about. It's meant to be more narrative, and less numbers-focused. Maybe in Anarchy the option to pre-edge vs. post-edge isn't really about which has the best probability in a given situation, it's just to give the player rolling the dice a choice about how to go about it... I can think of lots of times people at the table have said "these dice just aren't rolling well for me, I'm going to switch to those other dice." That's not about increasing the odds, its just about making a change based on how they feel about their luck. In a narrative-focused game, I think this is probably a similar option, even if the mathematical difference is inconsequential. Sometimes players might just think it's fun to roll a bunch of dice and see all the hits their pre-edged 4s, 5s, and 6s make.

Personally, I think that exploding 6's in Shadowrun are even more fun for the table than making 4s a hit. "Wow, roll it again! And again!!!" But, unless they also put into Anarchy that you can add the edge dice to the pool when pre-edging, I don't think exploding 6's would be enough of a benefit on their own. We'll just have to see how Edge is handled in the final Anarchy rules.

Really doesn't matter if it's tweaked or not, there will always be one statistically better option for any given situation.

IMO Pre-Edge should be "Better" because post Edge gives you the option of seeing the result first. So you know if you need two hits and you get two hits, you save your edge.

Agreed. And pre-edge is way more fun imo.