The tooltip says it prevents spells from being interrupted while casting at the cost of resists. Is this consistent with how it works on this shard? Do people use this so that they can dump without being interrupted? Do you have to choose between magic reflection and protection? I was wondering if I should bother casting little interrupting spells when someone tries to dump on me or if I should just let them and heal and pot through it then counter engage after theyve used their mana.
No the tooltip you read is from the Age of Shadows expansion for UO the information you're looking for is here http://uorforum.com/threads/the-protection-spell.6339 Yes you have to choose between magic reflect, reactive armor, or protection. Once one spell has ended and one minute has passed you can choose again. Whether or not to use protection, reactive armor, or reflect is situational and I'm sure everyone has their own opinion here. 90% of pvpers use reflect at all times. Protection certainly has a place for being able to cast without interruption, but I see it cast more often in tournament/duel settings.
Everything Mes said is correct. I will often use Reactive armor on a tank mage when I'm fighting a pure mage in the field though, which might seem odd. To me it serves as a way to interrupt my opponent more every time they punch me and that is of more value than reflecting a few spells or Mana Drains from my opponent. That's just one example of how opinions vary like Mes said.
Hate, you use RA to avoid stun punch or is there some other reason you would try to keep RA up against a mage even if reflect might save you 30-60 possible damage points that have to be healed through? It's an interesting tactic just wanted to know the rationale.
It doesn't avoid stun. What it does is interrupt my opponent when they punch me. Between weapon swings and purple pots those self disrupts my enemy receives due to me having RA on really add up and become an irritant at times. Plus how many pvpers actually cast on you when you have Magic Reflect up? They don't, they simply nullify it with a mana drain wand and you wasted your mana putting it up. The only time I use MR is in group pvp. The RA tactic I use is pointless in a group fight.