Yes, very succesful if you catch the secondary ferment just as the first is finishing and keep constant temps throughout bottling and secondary. The problem is getting rid of the sediment on secondary. Leaving it in the bottle isn't a real option unless you refrigerate really cold and pour a whole bottle of bubbly in one go as the sediment is quickly dislodged by the bubbles.
I have had some success in freezing the necks and extracting the sediment in a slug while holding the bottle upside down over a bucket but its a really messy job and you have to be a quick with the thumb and then bang in the cork almost all in one go.
Next batch I'm going to try and freeze the whole lot in the chest freezer and then gauge out the plug of sediment.
Ps I've experimented on several batches and have had a few that I would class as demi-sec and a few that are brut, like champagne which is how I prefer it. In my experience when drinking, the bubbles give the illusion of sweetness to the drink, so if you are after a Champagne like experience, then experiment with brews, adding lemon juice and getting the brews as dry as you can. Anything other than bone dry will appear demi-sec, anything medium will appear sickly sweet like Lambrini :sick: :sick:
A good tip is to make half a 500ML PET with the rest of the bottles, just as a check on how the secondary is doing and how clear it is so you can monitor when to extract the sediment.
I did one of my first brews in a 2L pet bottle and had to release some of the pressure after the first day of ferment, but its almost impossible to get a clear glass once you've brought the bottle back to vertical after pouring a glass.
Ps another tip is have a target ABV after the first ferment of not more than 10%