I can't advise you on Spoodles vs Party for the Senses (actually haven't done either )
The concerts are totally first come first serve, though there might be some reserved seating for special groups (like the PftS people?) - My understanding is that it's basically like the Candlelight, without the dinner package component.
I LOVE the Food & Wine Pairings. You get three appetizer sized foods (not appetizer sized like the kiosks, but more like the WDW restaurants, maybe a touch smaller) - and 3 wines - usually one food that's more desserty.
The only other 'extra cost' thing I've done is one of the Sweet Sunday presentations they had last year, and I enjoyed that -but it just doesn't work out with our schedule this year (arrive Sunday, leave Sunday).
Our (my sister and I) top three pairings we wanted to go to were Marrakesh, Italy, and Le Cellier, and since Italy is on Sunday, we are just going to go for the 2. I'm not sure about the other restaurants, but I know that LeCellier does different wineries/food each time. There were A LOT of people at the LeCellier one last year that had been to just about EVERY LeCellier pairing. I missed by a week or two a pairing they had that was 3 different ice wines, paired with at least 2 non-dessert items. That would have been interesting.
A couple years back, the pairing at Alfredo's introduced me to two wines that I bought when I came back home. Banfi Princeppesa Perlante (I don't have a bottle here, so that Princess word is probably way off in spelling) which is a very lightly effervescent white wine, and Banfi Rosa Regale (a rose sparkling wine - goes GREAT with chocolate!) I have made a point of getting a glass of Rosa Regale and a chocolate dessert every year since at one of the kiosks. Last year, I even treated myself to an extra glass one morning from the Fountainview bakery that they sell wine from during the fest.
The pairings are also fairly 'single' friendly, since you're seated with others. Unless you're super outgoing, I'm not sure how single friendly the Party for the Senses would be. It's actually one of the things that's kept me from doing it on my solo trips, and this year we're doing the TOT 6.5K which is Saturday night.