One of the things I find a bit confusing is how people choose to gift in MAA (iOS). For various reasons that I've thought about yesterday , getting as much out of each Spec Ops is the most important because there is little alternative to obtaining Spec Ops gear, heros, or 5-Star Command Points after a Spec Ops is over.
The way I see it, +2 and +10 Energy comes along with sufficient frequency from rewards from visiting allies. There is no reason to gift energy (granted, I'm a casual player). I'm willing to accept some +1 Challenges during PvP seasons. But I get Full Energy and 5 Challenges from the daily PvP roulette sufficiently often, that it makes it unnecessary to receive either of these gifts.
I've never completed a Spec Ops where I've felt that I got everything I wanted from a Spec Ops. There's usually 1 or 2 more missions I could 5-Star and several Spec Ops Boss/Epic Boss gear that I didn't get. For these reasons, I think people should only and always gift Unstable ISO-8 during a Spec Ops. Some people, toward the end of a Spec Ops season start splitting their gifts so that it's 5 Shield Points and 5 Unstable ISO-8. That seems like a good compromise, but it takes 10 or 20 Unstable ISO-8 to complete deploys and battles. The smallest unit of trading Gold for Unstable ISO-8 is 1 Gold for 10 Unstable ISO. That means, each day between gifts from allies and rewards from visiting allies, you can get 65 Unstable ISO, and so every other day you get a number of Unstable ISO divisible by 10, which is an actually useful number. When allies start throwing off the gifting, you end up with Unstable ISO at the end of the Spec Ops season that can't be used.
My personal gifting etiquette is to gift all Shield Points when there is no Spec Ops running. For fun, perhaps sprinkle in a seasonal item now and then, but gift all Unstable ISO-8 when there is a Spec Ops running.