Quick answer = YSR
Long answer = YSR (Here's why):
Y is about 10% bigger than the 3 in every dimension
Y has an additional 5" of rear-seat legroom (priceless for kids car seats)
Y sits about 3" higher, has a higher significantly higher roofline and the seats are on 3" boosters (much better view of traffic & surroundings)
Y has a truly flat cargo floor with all seats folded and can hold much larger cargo
Y has an available factory tow hitch
Y has better resale value
Sure the 3LR is going to be faster, handle better, have more range and of course AWD.. but how often are you really using these features? Realistically speaking.. how often are you accelerating from 0-60mph using 100% of the available power? How often do you push your car in a corner so hard that you are reaching the cornering limit and your tires are screeching? How often do you drive more than 200 miles in a single day? How often do you need AWD to make it safely to your destination?
For me, the answer to all these questions is simple.. Pretty much never. Which is why I bought the YSR. I charge daily to 90% and that gives my "short-range" Y around 180+ real-world miles which is easily enough to make it roundtrip to 99% of the destinations I would drive on any given day. That 1% where Im taking a long road trip over 200 miles, I just hit a Supercharger to make it to my final destination like every other Tesla. The only difference the long-range version would make on a trip is stopping less to charge (maybe every 3-4 hours), instead of every 2-3 hours with the short-range. So in reality thats saying what.. that every other month or so.. I'd have to make 1 or 2 less stops to get to my final destination if I had purchased a long-range version instead. Chances are I have to stop and hit the bathroom every 2-3 hours when driving anyways, so the extra range is really a non-factor for my particular usage.
IMO the only thing the 3 really does any better than the Y is outright performance. So if you are the type of person who previously drove or always wanted a sports car then the 3 is probably a better choice. For everything else (especially someone hauling around a family) the Y is going to be a significantly better choice. Even if you were single with no kids.. the Y is still much easier for adults to get into & out, to unload/load cargo, to camp or sleep in, to tow weekend toys like a motorcycle or boat.. and with the popularity of SUV's in America (and hatchbacks in Europe) will end being much more desirable to prospective buyers when it comes time to sell or trade it for another vehicle.