Pretty sure we had a discussion not toooo long ago, but she is a very strong champion it's just she's muuuuch better suited if you have a team that will follow through with you. Playing her in normals and even solo queue can be frustrating because you'll engage in, lock people up and your team just doesn't follow. The range on all her abilities (besides her Claw) are very short ranged so you pretty much have to dive into the enemy team to do damage. If you plan on playing with friends and/or duo queue more often then she's fun, assuming your friends aren't retarded. She also does very well in top lane too, especially against a lot of the melee AD bruisers.
One of my most recent games with her (maybe like ~2 weeks ago) I had a TF middle while I was Lissandra top, it was a free kill top lane everytime our ults were up because of how easily Lissandra can follow up. TF ports in and stuns, Lissandra claws in, stuns, roots, slows, dead. It's one of the better things about her is she can set up ganks extremely well. (Makes me think Lissandra + Shyvana would be a pretty devastating combo)
She's a solid champion, but as I said, can be awfully frustrating in yoloqueue.