Been a while since I used one (Explorer), but my opinions were:
Very easy to push one-handed and up/down curbs etc. No problems getting on and off buses (London, through the back doors!)
Newborn loved the swinging underneath bit with the cocoon, sent them off to sleep really quickly and many people I know said the same. Toddler seat on top was fine.
When it got to 6 months trickier, as then mostly moved toddler to back seat and baby in top seat, because baby can't get out and walk so needs to see, whereas toddler could walk most of the time.
Can't recline for naps if 2 are in the buggy at the same time. Bottom seat doesn't recline for naps anyway.
No room for STUFF generated by children. Can't hook shopping bag/changing bag on handle or you bang a child in the head. This is the same for all in-line tandems though, in my experience. What you gain in convenience of not pushing a tank-like pram is lost in the storage. You learn to pack well and refine the changing bag! Make the toddler walk when you need the back seat for stuff.
Never ever folded it up. It stayed up in the porch, because to fold it you need to remove a seat, and it was a PITA (same for all I think). Used a Maclaren int he boot of the car, and made toddler walk.
If you are only TTC now, and you already have a 2.2 year old, they'll be 3 by the time you need something - I would seriously consider just buying a decent Maclaren you can use for a newborn too and seeing whether you'll really need a tandem when you get to it. You may find by 3 they are hardly in the buggy at all anyway preferring scooter etc (this was my experience anyway.)