Unlike rechargeables, the simpler, more reliable mains-only shaver powers through stubble with no decrease in cutting rate. Kind of like the difference between an electric and petrol lawnmower.
Had this shaver for years and years. Still going strong (with a regular change in foil and cutting block).
Braun have stopped making a mains-only 7 series shaver - perhaps they realise that buying one of these is a one-per-lifetime purchase... if only they would make it again, I'd buy one for my son.
These things are more or less bullet-proof. They do need new foils and cutters fairly regularly though. The new, slightly improved foil from the 4000 Series Combi Pack is less prone to damage. I clean mine with a few blasts of an alcohol-based surface disinfectant spray can - cheap and protects the parts.
The motor itself hasn't skipped a beat.
Great shave, especially on my face type, lots of sharp edges and leathery skin to deal with. My biggest disappointment with this shaver is the speed with which it goes through foils and cutting heads. I also have a Phillips Rotary head shaver (tried that because it was a gift), I use it twice a day, 12 months now and I haven't had to change foils or heads. With the Braun I had to change both three times in the first 12 months. gets a tad expensive.