Years ago, they were fine. If it showed as in stock, it would ship within a week and you'd get it in decent time. Amazon has definitely changed our expectation on shipping/receiving though.
Now, even if it shows as in stock, they still don't usually ship for weeks. I won't order from them anymore. I suppose, if you really don't care about when it comes in, then it's ok. They are a reputable site, but definitely use their logistics algorithms to minimize their costs for shipping and distribution, and that results in slow shipping.