Your armor is one of the essential items your character will own, there are plenty of options you can choose but which one is the best? Well the best is always the one with the higher grade with the most stats but what about the alternatives?
There are a few types of armor, depending on the grade of the item, once you finish up your main quest line, you get a set called "Exalted Set", same appearance as the R99 set but the stats are the same as a +6 R99 set, the vast majority of players change that armor with their first chance, its good to have it on an alt support class but that's it.
Then you have the Blessed Exalted set, which is only available though the Einhasad Gold Coin Shop, ( or in some cases, they give it out for free in various events, so far there have been 2 instances that it was given out, when the Death Knight class was released and in the 20th Anniversary). Now the pack, contains much more items than the armor itself but our focus here is the armor. For its price the armor is great and for certain classes its an amazing armor to keep however there are some aspects of it where it does not make it an ideal choice, for example, in the Red Libra Event, you cannot change it from one type to another, Light > Heavy > Robe, you cannot trade between characters or toons on the same account, you cannot augment it, cannot add/change appearance, element resist is up to 120 element per piece and enchanting it costs EGC, although you can enchant it to +20, the stats increase up to +10, after that armors that are +12 and +20 are used in collections.
As far as the other armors, there are still 2 more options the R99 and the R110 armor sets, those armors are the best option once they are +8 and +10 for the extra stats each one of them gives and of course if they are bloody (for PvE), dark (for PvP) or limited (both PvP & PvE), R99 is usually bloody or dark and R110 can be all 3 options.
If you are trying to make a choice on armor your primary focus should be PvE mainly due to the -20% damage received from PvE and you also get an extra 5% damage increase. Bloody R99 armor, is a rather old armor set, can only support 3x 120 element on each part, is pretty cheap and has all the features available, can add 2x Soul Crystals on each party ( Tersi & Pa'agrio's), can augment it, can add/change appearance, trade it and if of course you want, exchange it to another type during Red Libra events. Again at +8 is where all the good stats are but there are not many of those around, most of them are +10 and cost "usually" 1/2 the price of a Bloody R110 +8 set.
R110 armors is currently the most used armor either +8 or +10, since the L grade armor has been introduced, you can earn +20 R110 limited armors from events or you may see people selling +12 or +14 armors. Even for R110 armors, the stats stop at +10 which is what most players own currently, since I mentioned upgrading the R110 set, you need a +30 Limited set and a lot of various materials to upgrade to L grade, something very few people have done so far.
Those sets usually cost quite a bit of Adena but its worth it since they give a lot of element resist, 3x180 on both armor and sigil along with everything else that the R99 armors have, can trade (if not augmented), augment it, enchant to +10 ( if +8), can add 2x Soul Crystals on each party ( Tersi & Pa'agrio's), can add/change appearance and exchange it to another type during Red Libra events.