ZETH, by Randy Heit, is a revised version of DETH, and as such is compatible with Doom, Doom II, Heretic, and Hexen. ZETH was created to take advantage of the extensions to the Doom engine introduced by ZDoom.
Because ZETH 4.17 was published at a time when ZDoom was at version 1.23 beta 33, it is a bit quirky in that when a ZDoom-specific level is saved, any lump types introduced since then (e.g. DECORATE, KEYCONF, DEHACKED, or TERRAIN), if present, will be unceremoniously deleted. However, it will leave the five original Hexen lumps (MAPINFO, ANIMDEFS, SNDINFO, SNDSEQ, and BEHAVIOR) intact. This can be worked around by finishing the rest of the map first, testing and polishing the layout and play balance, and finally adding the newer lumps with a utility such as XWE.
Once understood, however, ZETH may become an author's standby. Its clean interface is second to none.