If fitting a Combi, then it's Intergas all the way, don't touch anything else in terms of installing combis. Dead easy to setup for CH and DHW heat inputs for example. Simple to service. Easy access to parts. Good support from the guys at Intergas. Fewer working parts than many other combis. Condenses in DHW mode. Worked on the earlier versions on the market (Atmos Intercombi), only ever came accross 1 heat exchanger that had gone faulty, but that was due to installation error! 10 year warranty on the heat exchanger and it's easy to clean. These are cracking units and are great for building a positive reputation for us installation and servicing engineers.