I am playing BG1 vanilla (no mods) with a good aligned party, with a reputation of 20, currently using Branwen. The opportunity is coming up soon to add Viconia. Is she a better Cleric than Branwen? Is it worth trying to use her in a 'good' party with a high reputation? If I kick Branwen out, is she gone for good, or can I can get her back? I like the idea of having a drow in the party, so am curious about Viconia. Thank you!

My party is:

Me - Ranger/ Cleric multi - doing more tanking at the moment
Minsc
Kivan
Imoen
Branwen
Dynaheir

They're both single-classed clerics, so there's not much to choose from in that regard. Branwen has slightly better stats (notably CON, WIS and STR, though Viccy has better DEX) and can cast Spiritual Hammer as a special ability, which can come in handy early on. Viconia, as a drow, has a very impressive magic resistance. That can be a two-edged sword, however: in unmodded BG1, magic resistance also blocks beneficial spells. Like healing.

However, reputation-wise adding Viconia may not be a good idea. She'll drop your REP by 2 points upon joining... no big deal. But if your REP goes up again afterwards, she may decide to leave the party.

Branwen, being neutral, may grumble a bit about REP 20 but she'll never actually leave.

Edit: Ninja'd by hickory, who's right about Kivan being even a bigger problem than the REP thing.

If you really really want Viconia in good party you've got to use mods. So stick with Branwen until you'll find Yeslick, he's lawful good fighter/priest so much better in melee than both of these clerics and capable of using same spells (only a little bit later). No brainer :P

Thank you very much for the responses. I marked Hickory for the solution and +1 to Jason_the_Iguana and Hemaka.

I know this was marked as the solution, but I have a tangential question about one of your statements regarding Branwen. My first playthroughs were unmodded, and I thought (memory a bit fuzzy perhaps) Branwen would always wait around for you if you wanted her back. Something about her being forever indebted to you for rescuing her from being turned to stone. I've since played with various mods, and so the waters are perhaps a bit muddied for me.

No. With the exception of Imoen, most NPCs will disappear forever if your reputation is above or below their alignment comfort threshold. But that is not the whole story. Some will disappear no matter what (Garrick, Jaheira/Khalid IF they are left at the FAI and you clear Nashkel mines without them, Skie and Eldoth. There may be more.) In Jaheira and Khalid's case, it has nothing to do with alignment/reputation, but a stupid FAI area script that removes them after chapter 2. To keep them in such a circumstance, speak to the mayor of Nashkel to ensure their loyalty, and remove them anywhere BUT the FAI.

Branwen is neutral, but she will not stand for your party going to extremes, just like any neutral npc.

I rather choose Viconia lol, she's just an awesome char with great backstory, from the player's pov that is :P.

Is Yeslick a dual class or multi. Not sure if I would want a multi-class since I am already a Cleric/ Ranger multi and have Kivan and Minsc. A straight-up cleric may serve my party better.

Yeslick is multi-class, and inferior to Branwen in all stats except STR and CON (+2 in each case). His STR gives him NO melee bonuses, and his CON gives him +1 HP/Level. Considering he is multi, he is inferior as a cleric in every way that counts.

Labeling him inferior "in every way that counts" seems misleading to me, if not down right inaccurate. I realize that you've only said he's inferior as a cleric, but I can't shake the feeling that you are implying he is inferior as a character. Yeslick brings some other things to the party along with his cleric levels. He even has the same WIS, so Branwen doesn't win there.

If all you care about is adding cleric spells (and expect nothing else from the character), then sure, Branwen wins. She'll level faster as a cleric because she isn't splitting class xp, and it looks like she'll be one level higher as a cleric at the cap. But if you look at more than just number of cleric spells, it isn't so clear cut. Yeslick adds a bunch of fighter levels, so he'll have better THAC0 (more damage overall, since he isn't missing as often!), he'll probably have more hp (I haven't crunched the numbers to verify this), some of his saves will be better, extra strength can translate into better AC while carrying the same loot, and he's got that bonus Dispel Magic compared to Branwen's Spiritual Hammer.

Here's a post from someone else on a different forum entirely, comparing the two.
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At the TotSC XP cap, Branwen will have a wopping 1 extra 3rd and 4th level spell over Yeslick.

Yeslick counters this with more HP, a better THAC0, an extra Attack per Round (assuming he's specialized), a better special ability, and better saving throws.

I've made my decision: I'm adding Branwen until I meet Yeslick, where she'll be leaving my party.
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He is, and it isn't. You said it. Your problem, not mine. The question is about pure clerics. Let's not bring 'other traits' into the argument, else we might as well compare every single character.

Actually, the question was about who is the better cleric, not necessarily who is the better pure cleric. OP only gave two that he was considering, and someone else suggested that a third cleric might be better than either of the first two.

Yeslick is a candidate for "better cleric". Most characters fail right there, lacking clerical abilities either mostly (paladins/rangers) or entirely. Considering only clerics (though druids could fulfill most of the same functions), leaves 4 candidates: Yeslick, Branwen, Viconia, and Tiax. Viconia and Tiax are evil, causing problems as noted above (and Tiax is inferior as a cleric besides). You've given reasons for why Branwen wins over Viconia, but dismissed out of hand why Yeslick might be better than Branwen. Clerics do more than just sling cleric spells (at least, I expect them to do more); fighting ability and survivability are both relevant traits for a cleric. You, yourself, brought up aspects of fighting ability when comparing the two.

I bet that my reputation must have been suitable for her return, then. Because I know I've dropped her and gotten her again. I usually use the same small selection of party members (many of the other NPC's are too weak for my power-gaming tendencies), and the ones I add, I usually keep throughout the entire game, so I was unaware of some of those other quirks. Amazing how many little mechanics are built into the game that can easily go unnoticed.

No I haven't. I gave a specific reason why Yeslick is inferior. Stop arguing semantics.