I've played both Viconia and Anomen to the end and IMHO Anomen (with Gauntlets of DEX) is a FAR better tank than Viconia (even with a STR belt). His advantage comes from being a dualed fighter and being able to advance his weap profs beyond 1*.
Obviously both will have excellent clerical spellcasting abilities by the end of the game.
Another place where I believe Anomen shines over Viconia is in his Turn Undead ability, because he is a "good" cleric and Vicky is an "evil" cleric. Sure, being able to control undead may seem cute, but that can cause problems. I'll take exploding undead any time, any day.
Minor Spoiler
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The time I had Viconia in my party and I was clearing out Bodhi's lair the 2nd time with Drizzt and his aprty for allies, Viconia turned undead on the vamps and since her control was not complete, the vamps would flips sides... i.e. attacking other vamps, then attacking the good guys. When the vamps had been turned but then attacked Drizzt, this caused Drizzt's party to become enemies.
Good clerics don't have this problem. Either Turn Undead (TU) fails and does nothing, TU causes the vamps to run for a while, or TU explodes the vamps. No uncetainty. No mess .... well, maybe plenty of mess (i.e. exploding undead).