Once again:
1. Vita should actually be compared to 3DS and Wii U to PS4One. And in that case both are doing terrible. Comparing Vita to Wii U only makes sense if you dont want that it's two weeks old roadkill and not a happy, healthy bunny.
2. Vita has it's best months right now. Like last year. Because of japanese releases.
3. Vita is alive in Japan, dead everywhere else.
4. Sony has been doing a lot, like the Mega Pack being sold for 3DS prices. And PS+ as well as crossbuy definitely help it. Firesales for Vita and Vita TV sure helped to sell at least a few in the west.
Wii U is in a bad shape as well. And Nintendo basically has done nothing to make Wii U more attractive. High price, advertising only in kids tv at least at my place...
But selling way more software, most of it first party. At least physical copies.
Right now it is like the guy with the lung cancer insisting that the other guy with the brain tumor is in a worse condition.