I have been to SoapCon 3 or 4 times and thoroughly enjoyed myself every time. It is well worth the registration fee, and when there are workshops (there have not always been) they are also well worth the extra fee.
Carrie of Nurture Soap did a mica color mixing workshop at one of them, that both I and another member here attended & it was a fabulous workshop. She even gave each participant a set of micas & a little mixer thing for mixing the micas to create your own colors.
Vendors who attend are always very nice, and put something into the participant give-away bags, so there are freebies that are often pretty cool. Another perk is that some of the participating vendors will do a pre-workshop order where you put in your order & they deliver it to you at the workshop without having to pay a shipping fee. AND at a sale price as well. And they all seem to sell wares/supplies both days, but usually on the last day, prices actually go down so they don't have to take it all back with them. I've got some great bargains that way.
The speakers have all been pretty great, and I've had the opportunity to meet Dr. Kevin Dunn at least 3 times because he is a regular at SoapCon & a very down-to-earth and educational fun speaker, as you might expect. Clyde of the Clyde Slide was one of the speakers one year I attended, and he was also a very fun guy. There is usually a speaker from the Guild and a couple of times a speaker who addressed the legal side of things (US related, of course).
One year, even, I think there was an SMF member from out of country who attended. I wish I could remember who that was. It's really fun running into SMF members who just happen to be there. Sometimes I knew they were going to be, and sometimes it was a surprise.
Plus meeting Kathy McGinnis is fun, too. She's a very nice person and a lot of fun. And old friends from my first year of soapmaking. My soapmaking teacher is always there, as well. She lives in Ohio. I took two of her soapmaking workshops as they were the closest ones to Illinois (2 states over) and I really wanted to take a class of some sort. I liked her classes so much, I went back for an advanced class a year or so later.
And I can't emphasize enough how great the 'free raffle' is! You get a certain number of 'raffle' tickets with your price of admission (included in your packet when you arrive) and then at the very end of the workshop, there are drawings for multiple prizes. I won some fabulous soapmaking supplies at SoapCon almost every time I attended. In fact one year, I don't think there was a single person who did not go away without a prize.
I have never been to the Guild's conference, and I'd love to, but I can guarantee that the smaller conferences around the country are a lot of fun.