Help with finding a good 55 3D TV-where to start? LG 55LM4600??

Ok, i know this is an open ended question, but i currently have a 2010 model Sony 55EX501(sometimes known as the 55EX500), LCD HDTV. I am trying to decide if it is worth it to upgrade and go with 3D now. I do have the 3D blu-ray, Harman-Kardon 2600 that is 3D ready, and directv for 3D. Im trying to find something that wont break the bank in price, under $1500, lower the better, but will pay for a decent set. I definitely want something that would look as good as my sony is, which i think looks really good myself. From what ive found, it seems the led lcd is the way to go, is that correct? what are some good units to look at? Is a passive 3D ok to get so its like at the movies, or do i have to go to an active set? I was looking at the LG 55LM4600 at costco which is at a fantastic price i think there, it looks good in the store and the 3D preview looks great as well, but is it as good or better than my 3 year old sony? Is there something else i should be looking at as well? i dont really need the smart tv features, as my blu ray player has all the apps on it i need like amazon, etc. Any help or models and prices would be helpful, thank you!