I use a transition bag. I like it because I can fit everything in it, (it even has a race day checklist printed up on it), and it works back pack fashion. So if I end up having to park really far away I can put it on my back and ride to the race area. They are expensive but I got mine as a Bday gift from my DH. He loves me.

The downside of tubs (besides having to carry them which is hard to do if you're pushing a bike along too) is that they take up a lot of room in your transition and if it's a crowded race you may not have space for a tub.

I take things out of my bag and set up my transition, then I put my bag aside out of the way of the competitors. That way I need minimal space and can usually get a better spot in the transition zone.

But of course, I tend to show up at the last minute. If you're early none of that is an issue.