I think the 400HL only refers to the enlarger head, (light source and multigrade controls) and not the actual enlarger itself which could be De Vere, Durst or many others. Neg carriers, lens flanges are quite easy to find second hand as are all enlarger lenses. However, the 400 was the model before the 500, and if you have any problems with the head it may be difficult to find replacement parts or get repaired. Not sure where you are in the world, but in the UK, (South East), I know of two places which can look at 500s, though the spare parts are getting more difficult for them to find. Not sure if they could repair a 400. I think it also has a more limited range of grades, maybe 0-4 though would be best to ask someone else as I've only used one once years ago in a darkroom workshop.