I've now had time to download and play some of the tables... the verdict is... The Pinball Arcade is friggan awesome!.... and this is with a pretty aged machine. The main core of the machine is 7 years old. My main PC monitor only goes up to 1680x1050 and at that resolution with no options it looks pretty damn good.
I went ahead and upped the Antialiasing to 8x and turned on the post processing and ball reflection to high and it runs at an even 60 FPS solid according to FRAPS. My pc is pretty old too overall. It has had some upgrades over the years, but it is a Q6600 Quad core running at 3.1GHZ, 4 Gig of RAM and a Geforce 8800GT running Windows 7 64 bit.
I have not noticed any flipper lag regardless of those settings. Compared to the iPad I think the graphics look quite a bit better. In BOP and TOTAN the lighting looks very impressive. Just looking at the light bulbs around the brides head in BOP look amazing. Overall the tables have a MUCH better appearance and presence. Some of this I believe is resolution and the other part is the fact that a real gaming video card has a lot to do with how the specular and color effects are applied as opposed to the piddly processing in the ipads.
Like I mentioned before.. as soon as full screen cabinet, backbox, and DMD mode is implemented this setup is going in my VP cab as another tool in the toolbox for it to run. My cab only has 2 screens as I use my backbox monitor for the glass and DMD, but honestly even if it had no backbox support or just static backglass playing these tables full screen with a DMD would be amazing.
I can only imagine when I try this out on my other monitor or my TV that it will look even better. It will also give me a benchmark for how wimpy of a system can perform at an acceptable level.