Thank you for your replies - all are saying the same thing - but from different perspectives.

My take away:

1: I do not need to accept common to get the uncommon equip.

2: Yes there is a drop rate for rare/mythical within each class of equip.

3. Class of equip is determined by BG level. 1-20 / 21-40 / 41-60 / 61 and up.

Tips:

1: Upgraded common is better than plain uncommon - but takes moonstones

2: Hold some equip in reserve to swap out and upgrade when you can - then play them.

3: Upgrades with moonstones gets very expensive the higher the class / quality of equip.

Comment:

Yes we get more equip chests than the keys to open them. At least with the new Mar'eth quests

there are Class IV keys to win - gives me a ray of hope for the upward climb :)

Thank you !!!

There is another hurdle so beware

A lot of equipment has reduced power, so should not be upgraded

All mythical rings give 10% regardless of class, but other gear can vary a lot

You need to collect the best possible equipment and try to find 2 of each ring

You need to find weapon and shield that give 20% and helms, armour, gloves and boots that give 15% if possible before using too many moon coins

With the very best equipment you can enjoy up to 70% on all units by equipping 2 identical rings, and swapping them as needed

Snowgoon said:

There is another hurdle so beware

A lot of equipment has reduced power, so should not be upgraded

All mythical rings give 10% regardless of class, but other gear can vary a lot

You need to collect the best possible equipment and try to find 2 of each ring

You need to find weapon and shield that give 20% and helms, armour, gloves and boots that give 15% if possible before using too many moon coins

With the very best equipment you can enjoy up to 70% on all units by equipping 2 identical rings, and swapping them as needed

I'd worry more about the class and rarity than the exact power of each item.