The designs of pre-manufactured homes have come a long way since the old “doublewide”.
If you’re planning on living in a seismically active area (CA) – then the added advantage is pre-fab homes are designed to withstand pretty extreme vibration during shipping – so they weather moderate earthquakes better than most built in place homes. The steel framing is part of the reason.
We seriously looked at prefab when we were first looking at our companion unit… but there wasn’t anything of the right scale with the ADA features we needed.