Most recent commercial jobs, I have worked, have LED fixtures. A couple of notes.
Heat is not a problem so the metal fixture, you are familiar with, are now plastic. The LED's are internal on PC boards. They don't seem to be user friendly related to repair, more of a pitch the fixture and get a new one.
Last job, a few months ago, we needed an additional fixture and was told it was obsolete. I checked accounting and the fixture package wasn't completely paid for. Obsolete before the fixtures were installed. Note that lighting is a quickly changing market.
Most of the fixtures we installed, were two stage, with a Hi/Lo/Off control. Wiring was different, also required motion sensor(s)/no one in the room/off mood. This is standard energy efficient practice, Pennsylvania UCC (Universal Construction Code).
Some say that current LED technology will be quickly replaced with more efficient fixtures.
All the fixtures came with a plastic cover, that was to be installed with the fixture and removed after final cleaning of the building was done. Dust and dirt with the new plastic fixtures appears to be a problem. We were cautioned about using cleaning agents on the plastic fixtures.
One of the big changes is in the recessed metal can light market. You can purchase an LED fixture that , (with some work), will fit a standard octagonal box. Again heat is not an issue, looks very much like a semi-recessed can light fixture. These fixtures are relatively inexpensive, compared to the metal cans, standard practice for the last 30 years.
Quickly changing world. Most likely you will be removing old light fixtures and replacing them with new LED fixtures. Screw in LED lamps are available. IMO
Mike CT.