Are the bases the same for both aircraft as well as jr/sr status?

That is right as of today and most likely the future.
Little over 2 years bos e190 and am about 45% to 40%.
I will stick it out here till I can hold the same type of schedule on the bus.
I think many people think the same way or go right over at two years due to the type of flying( ie no 4 leg days, better overnights and more productive trips)

What's the difference in overnights? Are we talking, hotels, locations, or what?

Location differences listed by frequency. Same hotels for either fleet
Goto jetblue.com and click 'Where we jet' to see a map

320:
Everything west of the Mississippi
Florida
SJU + Caribbean
Occasional upstate NY/northeast city

190:
Mid Atlantic/ Northeast cities
Florida
SJU (maybe an occasional 1-2 other Caribbean spots)

Yes, same for BOS/JFK A320/E190

DCA domicile rumor still alive?

We will have a total of 30 slots and it will be a "focus city" but doubt we ever have a crew base there. You can get a bunch of dca overnights if you want them. I am on the 190 and bid for a lot of dc stuff and can be home an extra 5ish nights a month.

Cool, yeah I'm just trying to get an idea if I'm fortunate to get on with JB some day what the best airframe to go for would be for QOL. I really like the idea of being in BOS over JFK. Would it be safe to say if you can get BOS A320 in training to take it over BOS E-190 or the opposite?

I'd go BOS E190 for QOL no doubt. You'll have seniority much faster, which means better trips and days off/holidays/etc.

Maybe its because I live in base, but I think the QOL is great on the bus. I just have no desire to do 4 legs a day. 1 and done baby:). I have no idea about commuting though and Flyby has more experience here and has prob flown both planes. It really depends on the individual. Good luck.