I think they're brass rather than bronze, but no matter. Anyway, I installed them some 25 years ago on my former TR3A and I'm still using them. Did a lot of other things at the same time (Nylatron in the suspension pivots, rebuilt the steering box, etc.) so I can't really say which component had the most effect; but it really transformed the car. Less slop and much lighter steering. They've gotten really pricey though, so I'd go with the Delrin today. (In fact, I bought the Delrin kit with the intention of using it on the TR3, but decided to move the brass ones over from the wrecked TR3A instead.)
The brass ones did require some fitting, though. On one side, I had to add a shim to reduce play, while I had to trim the bushing a bit on the other side to keep it from binding. I also added grease zerks so they could be lubricated occasionally (which the Delrin won't need).
Oh yeah, the positioning of the idler arm bracket seemed to become more critical as well, since the brass doesn't deflect. I fiddled around a bit, getting it lined up with the steering box. (Both of them mount with oversize holes.)