The major changes I noticed between the two editions are as follows:
Limits prevent characters from being overly min-maxed. Each of them is centered around an attribute that is typically dumped in normal characters; the most important attribute for the physical limit, for instance, is Strength, though other attributes weigh in they have the same impact as Strength does alone. This means that you can't build a "never gonna fight close quarters" build and just dump strength and expect to do well in other physical areas, encouraging a well-rounded thing.
Mystic adepts get a huge buff. I'm not exactly sure that this is a bad thing; they still can't astrally project, but they get the powers of both mages (other than astral) and phys-ads pretty nicely. Were they still using the BP system, this would be a flaw, and I'm not sure about allowing them as the third pick on your priority system, but I think the reason that people are upset is because they don't astrally project as much as they should when not a mystic adept.
The priority system really makes things a lot better. It prevents some of the worst cheesing during character creation (don't get me wrong-it's still possible, but you have to know what you're doing and make some sacrifices).
Combat's been changed rather heavily on the bookkeeping, but not so much the execution. The Accuracy limit keeps pistols from killing Great Dragons, which is a nice touch, but also discourages just dumping into the newly increased skills and maxing them out right away. It also makes smartlinks a more tangible advantage, as do laser sights. Armor is now a single rating for stun and physical, which makes it a lot easier for new players to understand, and, in my opinion, more realistic.
Hacking's a lot better. Mind you; the wireless thing contains some logic holes and gimmicks with the new benefits it gives stuff like cyberware or laser sights, but hackers can enjoy a target rich playground with new rules for hacking that make prepping a hacker 90% easier and playing one about 50% easier; GM'ing hacking also became a lot easier. In addition, some of the more broken technomancer stuff has been revised so you now have a reason to play a decker instead of a technomancer every single time.
All in all, it's faster and more streamlined. If you want my "reviewer" version, you can check it out on my blog, but I've said pretty much everything I said there here, only without the sales pitches.
Helmets can be modified to include vision and audio enhancement. The full body armor's helmet for instance have a capacity of 6 (which is appreciable).
4th edition had a rule for targeting a spot not covered in armor and I think it's still valid and interesting in 5th edition.
Target an area not protected by armor. The attacking character receives
a negative dice pool modifier equal to the target’s armor (better
armor is more difficult to bypass). If the attack hits, the target’s armor
is ignored for the damage resistance test; the target rolls only Body.
This way having a full armor with a full helmet would makes it (almost) impossible (-18) to do. Which makes sense to me. At this point I would probably just call a shot to the head and hope to pierce the metal.
This is only if your GM is using this rule from 4th edition (which I expect to see back in the Arsenal book eventually).
Like Scrollmaster mentionned, there's also the fact that helmets masks your face but it's probably not suitable with some dress codes. Don't try to get in Dante's Inferno with anything else than a nice suit or dress.
Best Answer
When I interpret the Spam/Static Zone noise ratings, I see it as the following:
The City spam rating is one because that is where the more affluent people live. They pay for access to the city's grid, and typically these locations are going to be other businesses or higher-end residential areas, where they don't want the advertising, given that it will have a negative effect. The sprawl downtown has the same idea, but since they aren't throwing as much nuyen around, there's a bit more leeway on what advertising will do. There are going to be more people around, of course, adding to the chatter, even more so when you consider that since more will be on the public grid, both businesses and people.
For the commercial areas, even in an open air market, you're going to have everyone with a booth throwing out AROs and such to attract others. People are going to be doing searches for best prices, checking SINs, and all sorts of things. People are there to blow their nuyen, and marketers aren't going to miss out on the chance to grab your money before you have a chance to second-guess.