The Sellswords takes you to Menzoberranzan where you have to help your old "Friend" Jarlaxle to overturn the matron Mother. In general I would say the writing is good sans for the part that the drows seem to be a little to friendly and trusting in you. The scripting also works very well and I encountered no errors but no one really reacts to you attacking others. Even your quest giver Kimmuriel doesn't give a flying f if you kill the two mind flayers you have to convince to help you right after doing so.
Now to my main problem with most bigger quest mods. They tend to give you way to overpowered items and way to much XP. This mod is relatively modest in that regard but you still can expect arround 400k XP with a 6 member party and difficulty wise most of the fights are way to easy considering that you can access the area only in chapter 6. Rewards wise you get around 20k gold and quite some gems. You will also find a lot of high level spells and some of the best consumables. Most notably 120 Arrows of dispelling. You can also buy additional ones and also Arrows of Detonation.
Then there are 2 new pieces of equipment and a new wand. The Matron's Chainmal which is moderately useful and is something you would expect from such a quest. It has a AC of 2 and gives +1 Dexterity.
Then there is the Scimitar+4, Wraith. This one is quite powerful with 1d8+4, +1d4 fire damage, 1hp/round regeneration and 1 Strength and can only be used by evil characters. While it is quite powerful it is appreciated that it fills somewhat of a niche and the vanilla game gives powerful weapons for easier quests.
The wand is the Matron's wand and is basically a Finger of Death wand.
Overall a nice mod that gives a bit to much XP for its difficulty but I would recommend it.