Dont wear the jackles collar, you will loose the 2 of the 3 mr you get just from being human.
If they're planning on PvM only, it's better for them to be an elf for the extra 20 mana anyway.
Wearing the jackal's collar will reduce mana regen rate. It's not the straight 3 MR from JOAT or items, but it affects the base speed of your mana regen speed.
From here:
http://uo.stratics.com/content/skills/meditation.php
Base speed factor = (Meditation * 3) + Intelligence.
At GM Meditation or higher a 10% bonus is added to the base speed factor.
If you are wearing armor that you cannot meditate in, then the base speed factor becomes 0 (zero).
So even though the fire resist and dex inc is very attractive, I don't use it.
Regarding the race, I initially thought that the extra 20 mana is a blessing for elven warriors too, but I changed back into a human as the advantages that JOAT gives is much more.
I don't have med or focus on my sammy, so that's 3 mr from the 20 focus and 20 med.
I can use a 3 sec curse weapon from the 20 SS.
I also completed the spellweaving quest so that I can cast gift of renewal (even have 4 other joat spellweavers for a lvl 5 focus) on my Lesser Hiryu.
I have a 20% chance to hide when I need to quickly grab a bite/smoke/potty break/phone call! No worries about invis potion timing out.
Enough JOAT combat skills to qualify for max mana reduction on special moves even if I remove 1 or 2 combat skills.
If I swap out parry for ninjitsu, I will still have 20 parry. That's another 10% parry chance
