I guess the implied question is "Do all of you think the Lilypad will be more practical than what I have?"
Well that depends on the device you are designing, and what you consider "practical" for it. A Lilypad
can be a better choice for wearable projects (again this aspect of your device is unstated, but implied by where you made your post). However, it is going to have less space for your sketch (~14 kilobytes) and it will run at 8 kHz, half the speed of Unos/Megas/Leonardos. It would be more difficult to attach to a garment (though the right kind of enclosure could help), but the Nano
would give you simiar performance to an Uno in a reduced form factor.