To Me.....2JZ Is Favourite As It Can Be Boosted Quiet High On Stock Bottom END....!!
On Other Hand Rb26 Being Also Capable Of Making 500+Hp On Stock Setup But Its Not As Solid And Can't Bear Beating As 2JZ Can....!!
2JZ Being Bigger In Displacement Can Spool Turbo Quicker...Thats Also The Positive Point....!! VVT Is Also There To Support And Make Impressive Overall Power Curve....!!
I Think 2JZ Got More Options And Is More Solid Than RB....However Its Also Popular In Swaps As RB As RB Parts Are Quiet Rear Find Also.....!!
My Votes Are WITH 2JZ.....!! Just Make Arrangment To Lay All The Power Of 2jZ On Road
As Supra Itself Can't Hold 2jZ 
Lol @ 4EFTE Swapped In rx-8....He Might Have Matched Displacement Without Comparing The Rotary Vs Inline Difference And Power 