General good experience, but there are issues.
I feel like the experience just depends for me. I buy Astra Militarum. Most stuff has arrived on time/at a good time, nothing damaged yet. Prices are arguably ridiculous, just comparing against different stores. If Warlord games (A WW2 Model seller), sells 30 US Airborne 1:28 scale models for around 40$ that are honestly the same in detail and in quality, then why on earth can I only buy 10 Cadian Shocktroops for the same price? I'd check Amazon or Ebay before you buy Games Workshop. You can often find what you're looking for online for cheaper than it's sold on the official site. Also, nice thing about these websites is you don't have to pay a 10$ charge for any orders under 65$. If you CAN'T, well... just hope you need something expensive. And if it's not on Amazon, it's because it goes out of stock fast, and typically stays out of stock.