Elite was at one time known as Ex-Cell but went bankrupt several years ago because they were selling low cost/quality cold-water pressure washers to big box retailers. DeVilbiss Air Power, the consumer division of air compressor manufacturer DeVilbiss bought the remaining chattels and now supplies the same customers with the same products. DeVilbiss sold the division to a large conglomerate and (IMHO) had to change their name to DevAir to separate themselves from the image being portrayed by DeVilbiss Air Power. Some of the managers from Elite formed XL Manufacturing which morphed into Elite later. They followed the same low price policy and again ceased operations last year. They were building some of the units that Delco of Fort Worth used to sell, these units have been replaced by those manufactured for them by Ramteq.
Landa is one of the oldest pressure washer manufacturers in the US. It was started by Larry Loftus and grew to become one of the largest builders in the country, they are located in Camas, Washington. A few years ago Landa was sold to a unit of The Harbour Group under Greg Fox (a son-in-law of the owner). In the interim they have added, Rhino, Specialty, ASAP, Hotsy, Cuda, Hawk pumps, Tuff, Spraymart, Admiral Pump USA, Victor-Midland and I believe Bertolini. Under the group they are one of the largest pressure washer manufacturers in the world offering a wide assortment of quality and products. They range from no certifications to UL-1776 certified products.
Largo is a small regional player located Decaturville, TN. It appears there is some connection between them and the old L & A two-step pressure washers. They have a limited offering and contrary to any claims made on their internet site, have no better products than most other manufacturers. Again, IMHO, if they were as they claim then why are they not safety certified by an accredited third party to some form of recognized standard?
Truth be told, the dealer is of more value than the product. A local professional pressure washer delaer can your greatest asset. They have the knowledge, experience and technical support to keep you working. Decide on a dealer first and the product second. No one ever complained about spending more for a better product.
Hope this helps? Cheers.