Short answer; Yes.
Long answer; She's not a typical jungler, and can't properly gank until 6 (needs it for for crossing walls/gap closing), but her early clear sustain/speed is on par with Fiddlesticks, which is amazing because she's not a typical jungler. She's build mostly like an assassin but her W shielding and natural build make her quite good at taking hits, though she's not a real tank; you'll probably build more AP than HP. She's a good pick in this meta as a mid laner.
The only thing you have to get used to is curving her Q to hit all the targets you want, using it to gain vision (the debuff gives sight of enemies), and using R once on Moonlit enemies as a poke tool or on targets for pure mobility purposes. Buy her, now!
Note: I love Diana.