With the tower, my opinion is you can't go wrong with either view. MK viewing options are abundant, either from the north end stairwells, the 4th floor observation deck, or the BLT walkway - so even with a standard (lake) view room there are places to get in a little MK view fix.
I find them very opposite experiences though - with TPV... it's so alive with action, motion, things to look at (MK, monorails, boats, other resorts, etc). There's a real energy that is hard to articulate - an energy I find exciting/invigorating. There are some downsides though - you get a lot of parking lot view in the foreground and you do have the ever-present buses on World Drive from early AM to late at night. Bus roars and beeps can occasionally be heard. I find these part of the buzz of a TPV room, but some may not. A no cloud summer afternoon/evening will be a scorcher on the balconies on this side. Like literally, cook an egg hot.
With the standard (lake) view - I find it incredibly peaceful and serene. The sunrise view is fantastic. It's pure relaxation. A nice respite from a typical busy WDW day. Watching EWP from your room is priceless.
For either view I do usually request to be on the north end of the building as that's the side away from Chef Mickey's. It's not really an issue right now given lower occupancy, but in normal times I have on occasion been able to hear that song and the clanking of plates/silverware from my room (especially upper floor rooms - sound seems to travel straight up). So if I had a choice, I'd rather be on the north end away from that noise below. BUT, this is a very minor observation, not a deal killer (in my opinion).