We first saw the FS foaming degreaser at the start of the year and it certainly looked like a fun new way to get your bike clean, if it can ever be fun. In practice the main benefits are the ease of use and lack of mess. It's a bit lacking in terms of raw degreasing power but a great choice for a general clean. And it's so safe you could eat it – Mr Fenwick tests all his products by eating them, apparently – although it probably isn't recommended as a regular part of your diet.
Muc-Off’s water soluble degreaser is a very proficient solvent based cleanser that makes short work of accumulated grease and grime and to that end makes a very handy workshop companion. The fact it easily washes away without obvious trace or harmful effect is a real bonus-especially if you're working on a patio or more ornate surface. However, while in a pinch it will tackle headset overhaul, it struggles with waterproof marine greases and care is required on delicate finishes.