I think there are a few reasons I'm leaning towards a tacoma.
1) I feel like I can't wheel my runner it as hard as I'd like. The rear end of the 4runners feels like it hangs out more than tacomas. I'd like to wheel the Rubicon again, and I don't think I'd want to take my runner through the Rubicon. I thought I got it out of my system, but it really is a great trail and I want to go back. I have no doubts that a doublecab on 35's would make it through without issues.
2) I don't have experience packing the 4runner with gear. Each time I camp I learn a better way to pack the rig up. I've gotten pretty good at packing a pickup, but I haven't figured out how to pack a 4runner very well. On my last trip, I had 4 people and a dog with me. Maybe after a few trips I'll get better at packing with it. With a thule cargo carrier on the top I could fit all the sleeping stuff up there and have a lot more room in the 4runner.
3) I really like having a tailgate to cook on, sit on, and prepare in general. It's like having a table attached to the truck.
4) it's nice to put nasty, dirty things in the back without them being in the same compartment as the passengers
5) I love the storage space behind the rear seats. It's perfect for recovery gear.
6) I may want a RTT someday, and I can mount it a lot lower on a tacoma, yet still retain bed functionality.
7) in order to fit the same amount of stuff in a runner as a truck bed, you need to stack gear. That means gear is burying gear. Which means you're digging through sleeping bags, pads, coolers, stoves to find stuff.
A few things I like about the runner:
1) it's already built. I'm sick of building rigs, I just want to drive them. Plus this rig is clean and has every feature.
2) you can lock your stuff in it when you run into a restauraunt or store. Can't do that with a tacoma.
3) it's a little bit more driveable for DD, shorter wheelbase= easier to park.
4) it's already paid for and I don't have to worry about juggling funds to make it work out.