I have stayed at the WM Anaheim and the Peacock Suites within the last 18 months. Peacock Suites is a converted hotel. The 1 bedroom units are one large hotel room with a wall in the middle, the two and three bedroom units are two hotel rooms divided into pieces. We had a three bedroom at peacock suites and liked it, as mentioned the common area was small, and the kitchen was more of a hotel style kitchenette. All we used it for was cereal/toast in the morning. We ate the rest of our meals at Disneyland. That made sense for us because on our dates the cost of the Peacock Suites was less than the WM Anaheim by the cost of meals out for our family for the whole trip (based on our WM/Shell maintenance per point).
WM Anaheim is nicer in pretty much every way. They are purpose built timeshare condos. While not quite up to the Marriott/Westin standard, our two bedroom unit had two full baths, a full kitchen, in-suite laundry (shell has coin operated on the top floor), and a full sitting area. Our two bedroom at the WM was at least 50% bigger than our three bedroom at Peacock Suites.
WM Anaheim is relatively new, and Peacock Suites has obviously been recently refreshed. I found the beds/soft goods fine at both, and the service was comparable. Both are managed by Wyndham.
Location between the two is almost exactly the same. We walked to and from the parks twice a day from both, took <15 minutes pushing a stroller. They also both are on the Anaheim Resort Transit line, which will take you to the parks for a fee. I believe Dolphin's Cove isn't walking distance but is on the ART line, although I have not stayed there.
Anyway, I would be willing to go back to either, with appropriate expectations. We only used the room for sleeping (both night and naps) and eating breakfast, and were otherwise at Disneyland. Peacock Suites was quite a bit cheaper for us, but if they were equally priced I would choose the WM every time. One other factor is that Peacock Suites was valet parking for $11/day, while WM was self parking for free.