I've bought a couple of things from him off eBay and always had a pleasant experience. Anything I've bought came quickly, was well packed for shipment, and usually included one of his $1 parachutes (I think they were made for flares, and he must have a jillion of them).
My experience with Commonwealth Displays was a bit iffy -
I bought an old Estes Stinger from him off eBay. Shipping was very high - in fact, it was more than the closing bid on the rocket.
Then, it took several emails *after* I had paid him via PayPal to get him to respond. All in all, it took 3.5 weeks after payment to receive my order. Now, I did get what I paid for in fine condition, but it seemed very slooooooowww which was quite frustrating. I did not receive any extra chutes. Just my rocket (but I expected nothing more anyway.)
A couple of years ago I dealt with Commonwealth on some bulk kits for a Scout project and their customer service was fine. I haven't placed an order sense then simply because there are so many other vendor choices -- not because I had a bad experience.
I've bought from them several times. They confirm the order via an autoreply email and thats it, no order tracking. I've always gotten everything within a couple of weeks. Once they didn't have a motor I ordered (that their site indicated was in stock) but they deducted it from the bill. Watch out for HazMat charges with them on AP rounds though.
I have bought a couple of things from them through Ebay - and always had a good experience - delivery within 10 days to this side of the pond (I'm in the UK) and communication was great - no autoresponders just real people.
WHen you take into account the time difference and distance this was top notch service. Of course there is a better company out thery..... goes by the name of fliskits or something - Jim had my Tres over to me inside a week!
On a recent order I had some problems with some parachutes. After an email or two Steve was willing to fix this pronto. I even ordered some extra stuff on the replacement shipment. All came in perfectly. I give them two "thumbs up".
My favorite store, also because I live close by. An unbelievable inventory. It's the only place I've been where you could see every item offered by Estes, Quest, Custom, and a host of midpower and high power vendors all in one place.
Also, it's a real business, not a basement, or spare bedroom, operation, but it is only open 32 hours a week. I know there have been some new personnel helping out over the last couple of months who weren't very familiar with computers, but they were VERY knowledgable and helpful about rockets.
I've alway found them very honest and helpful, and the prices are way better than my local hobby shops. My suggestion is give them a try.