The local PA (zone 6b) nursery by me has a large (5yr old) black mission and a large conadria in pots for sale.  They also have small black missions.  What would everyone's recommendation be if they could only buy one larger plant?  Would you get the smaller black mission since they grow so fast?  I'd like to get one larger plant to compliment my smaller (2yr) negrone, neri 2, osborne, and sicilian that likely won't have many figs this year.

Both large figs, the one on the left is supposed to be the black mission and the one on the right the conadria...



Black Mission leaf:



Conadria leaf:



Nick

If you like negronne you will like Black mission they are in the same family. Conadria was sort of blah for me. I got rid of my tree last year. Your neri2 from Bill's figs is Marseilles white. There are better choices if you can wait such as a hardy Chicago variant for dark and JH Adriatic for light.

Negronne and Black Mission are not similar fruit.  Negronne is slightly-or-more berry with a jam texture.  BM is more of a syrup taste with a stiff texture, people analogize as pasty, and I think of as a partially hydrated dried papaya.

Conadria requires heat to ripen good fruit.

In fact, both of your choices are terrible.  Even if you could trust the nursery to have accurately grown Black Mission, BM is NOT hardy in the north.  It's not even really happy in Atlanta, so I understand.  You'll probably only get bland fruits outside of your hottest, longest summers in Pa from Conadria.  This is a sucker bet.  In pots, I would, hesitantly, go with BM.  However, there are just too many better choices worth the longer wait.

I keep everything in pots.
I have 2 varieties of Conadria and have been getting figs since they were 3 years old. Of the 5 seasons I've gotten figs they were excellent except for the weird rainy cold summer last year when they were a bit bland from over watering and not enough sun.
I always put my Conadrias right next to a large 8 year old Hardy Chicago as they ripen together and compliment each other well. 

I think Mission's a good fig but there are so many dark figs I like better. Certainly Kathleen's Black, etc.

Personally I'd pick the Conadria as you already have Negronne. 

I think with all figs it's hit and miss. Some seasons the figs are great - some they aren't. If you have the space to keep your figs and experiment with the water/fertilizer/sun/etc. then you can learn what they need to produce great figs.

Last year I watered far more then I ever have before and certain varieties like Conadria, Brunswick and White Paradiso produced sub par figs, but others like Mary Lane Seedless, JH Adriatic and LSU Purple thrived.

Anyway, the point is it's really hard to tell others in different zones and locations what's going to perform better for them.
If you read about a fig and it sounds like something you want to try then try that one -- but give it a few years and if it gives you figs you aren't happy with change its growing parameters and see if the figs change. Fruit trees respond to different conditions and their fruit can change in both texture and flavor under different conditions.

The reason diversity is so important is if you have different varieties you're much more likely to have trees that produce excellent fruit. It won't be all of them and it will be different year to year, but if you become skilled at caring for them even the ones that have "off" years will produce good fruit. 

I have friends that grow over a dozen varieties of cherries and there's one old black variety that's an unknown but was once heavily planted in the valley where they live. It's not very impressive most years but every so often it just goes to town and produces huge amounts of the best cherries I've ever had. Those cherries are so good it's worth it to them to keep several of these old unknowns around even though in the 30 years they've been growing cherries those trees have only been excellent 5 of those years.

Lots of great information everyone, thank you! Sounds like the only way to tell which one I'll like is to try them. I'll have some of the more recommended varieties as well though and plan on getting more cuttings this winter.