I've heard pretty much most of ARTPOP in HQ and at the moment I'm slightly unsure as to what I make of the album. As a pop album it's a solid effort. The core pop songwriting that was absent for part of Born This Way has thankfully returned and the songs are far more streamlined, also benefited by the lack of Fernando Garibary and the (highly welcome) introduction of Zedd and Madeon on the production.
However I can't help but be slightly underwhelmed by the whole 'ARTPOP' motif which doesn't seem to be much more than a guise to me. As I said before, in a 'pop' sense the music is on top form and it's by far her most consistent album to date, but while there is the odd homage to Bowie vocally or to her subversive niche lyrically, I don't believe there's actually that much on the album that really attempts to go as far beyond pop music to be considered as art, and that despite being branded as her reverse-Warholian experience it's no way near as ambitious as Born This Way.
Nonetheless the album is by far commendable for it's accomplished pop songwriting and delivering bucketfuls of brilliant hooks and vocal performances. At the same time though I believe that this is just commending Gaga for something we actually always knew she could do and just didn't deliver on Born This Way. In this sense I think the album can be viewed as a relatively safe attempt at creating a hybrid of art and pop. As an album it doesn't reach many spectacular heights having been promised with ARTPOP, but as just 'pop' it's a decent record - although I shouldn't be so surprised as this is something that's always been within Gaga's capacity.
Best of the bunch: ARTPOP, Applause, Aura's chorus, G.U.Y and possibly Mary Jane Holland/Do What U Want
Duds: Dope (by far), the songwriting in Venus, Aura's first verse
As SC said my opinion might change, especially once I listen to all of it in HQ in order