I hated the McLaren MP4-30 livery at first. It's boring, it's a little too much like what they've done for the last 10ish years, and Force India did something similar with a line running around the nose.
And yet I like it for its simplicity. That red/orange (depending on the light) pops against the black and they scaled back the chrome from last year (which I was not a fan of). Plus, with all the troubles they've had in testing, they're becoming the Loveable Losers in my eyes. They've been around forever. They need to succeed.
That being said, it'll be interesting to see if they change the livery at all for Melbourne, especially if they pick up a big sponsor.