I'm about to purchase some life vests and a couple of other things from them. It'll be my first purchase. I've heard some positive and some negative (mostly positive). In any case, they do support this very free forum that keeps us all entertained. So I'm definitely giving them a shot. You should too.
Ordering online is next to impossible in my experience. It is great they support this board the way they do, but price wise, its rare that I find a bargain on anything I need. I have noticed some killer prices on close out stuff, so it is worth watching or getting on their spam list.
I've used them for several purchases. Their closeouts and special purchases are often very good deals, and they're competitive on many other prices. However, their e-commerce engine leaves a bit to be desired, so I would highly recommend calling them and speaking with them over the phone if you have any large purchases or a list of items you need.
Unfortunately, I find myself agreeing with SmackDaddy.... most stores will have at least one bad experience, but my overall experience with Sailnet's store has been quite good, provided I didn't try going through the e-commerce portion for any complicated orders.
When we first bought our boat I ordered $1,000's of dollars worth of stuff from Sailnet over the next few years. Never a problem. If fact I had one guy there who I would call and ask for the deal of the day. He would always have a close out or some deal. IE, my kids had true foul weather gear for the price of plastic rain suits.