The most inventory and actually just a really nice place to walk around.
We've been getting plants for our urban balcony garden for years. Their prices may not be super cheap, but in line with what most are charging, and the staff are knowledgable and friendly.
For citrus plants (not sure about the other trees since we only experienced this with a small orange tree) it's actually kind of cool as they have a guarantee. If the plant dies within a certain amount of time, you take a photo of it, bring your receipt in , and they will give you store credit for other plants.
Also, if you are a regular customer, you get points every time you purchase, and you can redeem them for $ off your purchase. :-)