I made the switch about 2 years ago and I love them. Being able to dial in not only the float you want, but also the angle of the float is really nice. My right foot tends to angle out ever so slightly and is happier with the cleats set up like this. My number one tip for setting up is do not over tighten the screws! Do them too tight and it affects the spring mechanism meaning it can be very hard to clip out.
Ok so maintenance wise:
1. greasing pedals - needs to be done about every 5000km, I tend to do it whenever I replace a chain as it's a good reminder for me. Super easy to do, $0.50 syringe from the chemist and inject grease into the port until it comes out clean. Both pedals, 3-5 mins
2. cleat wear - the cleats will wear out if you don't look after them, coffee shop covers are essential. If you are really worried I'd recommend the keep on covers
that permanently stay attached. The cleats can be hard to get off you let the screws wear
3. lubing cleats - doesn't need to be done that often, just a bit of lube on the spring every now and then. probably once every 2 months or so?
So all up, they really aren't very hard to maintain and I think easier to set up than SPD-SL.
edit: also do the Sidi's come in a 4 bolts speedplay pattern? Either way make sure you get the carbon sole protector (basically a thin metal plate that goes under the cleats). Also you made need to drop you seat a fraction if the stack height is lower