We’ve got the Premium (here’s My Review) and it’s very good. The Smart Silence is fantastic, and we do use the Autopilot on occasion, but less so recently.
I’ve heard good things about the Melt, but we haven’t got it ourselves. We do have about 3 or 4 other app toys, and they’re fun, but as we live in each others pockets (especially recently) I don’t think we have as much use for them as some other couples. The Melt didnt exist when we got the Premium, but if it had been an option I would certainly have considered it (I’m also a big fan of the We-Vibe app, but have only used it with traditional vibrating toys, so not sure what the options are like for a suction one?).
Here’s a recent post extolling the Melt’s virtues: 
If you can squirrel out a %off offer code that’ll shrink down any price gaps, and may sway you one way or another. And don’t forget that if you’re Unlimited you get a 25% off £40+ voucher you can use as often as you like. 
And the Happiness Promise is a nice safety net if you’re on the fence. (the specific Happiness Promise section is lower down the page)