The new priority security worked well and very quickly just now. The gigantic queues posted earlier had dissipated and there was no one in front of me at priority security. As others have indicated, the signposting is a bit poor: you have to go behind the check-in desks and then veer right. There were no automated entrance gates but rather a person with a handheld machine checking boarding passes. I was very glad that SK had resumed paying for fast track at HEL...
The new technology worked very well in that all I needed to do was put my blazer and overcoat in and my briefcase on top of that. Belts and watches on and laptop and liquids stayed in the bag. It brought back memories of airport security in the early 2000s!
Others have mentioned the distance to the lounge. Since I'm on SK this morning, it's Aspire for me which is very convenient from the new security - particularly compared to the old setup of checking in at T1, walking to Aspire and then walking all the way back to gate 11 or thereabouts...