It looks like the 360 will not sell well in Japan at all, having only shifted less than 500k units in 16 months whereas the PSP has sold nearly 6m in 27 months. Sales in the US are very good for the 360 and only lag 2m behind PSP, but in Europe they only have half the sales so far.
The 360 is currently on 10m units compared to the PSP's 21m+.
With the recent PSP pricedrop and a pricedrop due over the next 6 months in Japan and Europe, I can see sales of the PSP climbing a little over the course.
I can't see the 360 getting near 20m units worldwide for sometime, maybe another 18 months plus anyway, but it all depends on what happens with the PS3.
I will work out what I think will happen later.
Prediction (June 12th 2017)
Permanent pricedrop for both PS4 Slim and PS4 Pro in October.
PS4 Slim $249 (October 2017)
PS4 Pro $349 (October 2017)