It's true, I've never had to wait longer than 3 minutes for a Spadina streetcar to arrive. They are frequent (unlike Bathurst Streetcar, UGH)
I've been taking the 510 a lot lately to and from my new home (Front/Spadina). When you get on at Front, it's nice and EMPTY! Once you hit Dundas St it really packs up with Chinatown shoppers on their way home (yes, sometimes they have smelly groceries with them). Such is life, I cannot fault a streetcar line for it's smelly passengers :)
The other good thing about the 510 Spadina is that its tracks take you UNDERGROUND and deposit you inside Spadina station, with direct access to BOTH subway lines. No need to step outside if it's raining or snowing.