The week before the 3DS price cut, sales hit an all time low of 3900 on a userbase of 1.3m. Sales jumped to 206k the next week for a 5100% increase (which is a factor of 51).
The vita ended its week prior at 11k on a userbase of 1.2m and if the same 51 factor was applied it would be 550k units. Of course it wont be that high but the factor of about 500% (50k units) that people are using seems low, but we'll find out soon enough!