I used both ELH and ESD. ESD are dimmer and cooler, which was good for me, but they have a vastly shorter lifespan and a much higher price. I use ELH now, and I solved the brightness issue with a layer a 0.3 ND filter in the 4x5 mixing box to keep my exposures about 20 s at f/8.

When you change to new bulbs, watch out for them having an even output, or your grades will no longer be speed-matched. You can check and correct that using the Ilford test that helps you select one of the 4 (or more for the CPM model) programmes on the 500C controller. It's not a big issue if they are not speed-matched, but if you use your 500H a lot it will make a difference in predictability of how the highlights and shadows change as you change the grades.