Upgraded yesterday. was £35 to have the premium for 240 odd days. That's just brilliant value in my book, even more so as I immediately downloaded Returnal, Pillars of Eternity and The Outer Wilds - around £100/£110 worth of games a week ago.
May downgrade to the middle tier in the future, but that'll be based on how much value/time I get out of the extended demos (which are, I assume, their way to upsell and will likely only have games that won't make it into this service)
Will see how this pans out, but, for me, and for this first period of time especially, it's fantastic value.