I make a lot of orders for RC equipment, shipping time seems to be improving, everything I've order this year has gotten here in 5-10 days and tracking info has been quicker to show up and more reliable. Just don't make any orders around Chinese new year. That being said Chinese prices have inflated to the point that I can often find a similar price here in the US for most items and get them in 4-5 days.
That's about right. Depends on customs and other mysterious bits. I've had shipments take a couple of weeks and I've had others take 6 (in fact 30 days seems a bit aggressive). It just depends.
The window is pretty accurate. I've had shipments take a week, and others take 1+ months to the exact same address. It is pretty much random and I just assume it's going to take longer than a month.
I always imagine there's a plane that leaves at regular intervals, e.g. twice a month. If you order right before the plane leaves you'll get the order sooner, otherwise your order just sits in some depot until the next plane arrives weeks later.