So it is about as hard to kill a 30 point Defender as it is to kill a 42 YT-1300 and a little less than a 33 point firespray.
Well, the YT has a lot of things that don't easily factor in. The 360 arc means it can attack you without exposing itself to fire, and it also has a lot of upgrades that improve its durability.
But with that asterisk, yeah. The Defender, Falcon, and Firespray are all in pretty much the same class where pure durability is concerned; the next step down is the Lambda, TIE Advanced, and E-wing, which is pretty nice company.
(It has only middling defensive efficiency, in terms of the points you pay to get that durability--but in that respect it's in the same "family" as the Firespray and B-wing.)