Well I'm going to throw a spanner in the works here. Just to present a balanced viewpoint.
Initially all my purchases through OPT were handled promptly and it was not unusual to receive deliveries more quickly than some Australian suppliers. However that has changed over the past 12 months. I have experienced significant delays, lack of replies to emails and followups and only received a reply after going over the top of the internetsales dept.
If this was an isolated incident then I would not worry about it, but it has happened too frequently of late. An example (but not an isolated one). My last order was for a $40 reticle illuminator. I placed my order online AND mady a followup email (considering recent experience) I sent another 2 emails until I contacted the boss. I received and apology and an assurance that the item would be dispatched the following morning. That was the 18th of Oct, my CC was deducted initially deducted the amount of the illuminator on the 8th of oct and the postage on the 19th. I have still not received the illuminator after nearly a month.
After this I will be sourcing my gear from elsewhere, no matter how extensive their collection of goodies is.
Caveat emptor