The UVs improve survivability and efficiency of killing things faster. In the hands of a noob player with lots of cash, the ultimate UVs won't protect against stupidity. A highly skilled player should be able to get by with just non UV 4* and even a 3* shield that offers zero status effect protection in FSC. However, with weaker gear, you may need to play more defensively and will take more time completing a floor. Many of the veteran players have just enough skill to almost solo FSC in great gear. Fighting the same boss strata is repetitive. Thus, as a veteran, you already know what to expect and how to counter pitfalls and attacks.

UVs and high skill will become even more valuable in PvP where you really need to be on your feet and think dynamically to counter the unpredictable playing styles and beefier gear.

For my playing style, extra elemental and resistance protection is noticeable when dealing with ranged attacks from many Red Rovers, Gremlin Scorchers, and anything that breathes range damage. To clear many foes with ranged attacks with a partner, we use our Grey Owlites to shield each other, instead of just ourselves. It allows for non-stop shooting. The shooter stands very close to the shielder for protection and keeps firing. As soon as the shield bubble turns yellow, the shooter puts his shield up and becomes the shielder, while the shielder becomes the shooter.

http://itinerant.wikidot.com/uniquevariants

Have you looked at what Max UVs look like on 5* armor and helms? If you had a Volcanic Demo suit and helm that both had max UV shadow it would be like having another piece of armor for that one damage type. I know the defense bars have a reputation for being sketchy, but having some good UVs on your gear could make the suit quite a bit more versatile.

Seems like there are different (viable) approaches; make your one ULTIMATE suit of gear and weapons or spend your time diversifying. I would favor having one ultimate rig, so that I'm not switching gear at the terminals all the time. For others, they might enjoy checking the gate maps and planning ahead and relishing in the mental exercise. (I'd like it better if the gate map were mapped to a key stroke!)

I think some UVs are pretty overrated and you definitely don't NEED to have them to enjoy the game. I do think that some UVs can seriously improve your survivability in less-than-deal conditions. Take into account that you may run a group with someone who doesn't know what they are doing or experience lag spikes from an astonishing new population increase or whatever.

I can say that with my current setup I have never been cursed by my Faust. Ever.