Lego, Duplo, Marble Run or something else?

[curlytoes]

My DS is 3 and loves building. So far he has a massive tub of megablocks, some plastic stuff with screws and joining bits and wheels which builds a big truck and some wooden blocks. I'm drawn to duplo for Christmas but is it too like megablocks? Is lego too fiddly for a 3yo? I love the look of marble run but have younger siblings to worry about. Suggestions, ideas?

My 3y nephew plays with lego ok. You can get a brick seperator widget to make it easier to take stuff apart. He's only just 3 the other week.

Really - a brick separator widgit? We love widgits and gadgets of all kinds. Thank you.

DUPLO is fab, for most 3 year old's normal lego is too fiddly. We have a huge box of it that now comes out for visiting little ones.

Marble runs are brilliant as well, but maybe best when a little older.

Lego is a bit on the fiddly side for my 4 year old - duplo is great! And if relatives ask what to buy him for christmas, another set is easy. Don't forget to buy a base board if you do go for it as they get really frustrated when their beautiful creations won't stand up on the carpet.

Mine were also bought a very small waterfall style marble run thing and it seriously mesmerises them! (PITA tho constantly picking up marbles)

The middle sized mega blocks (same size as Duplo) are half price in Argos at the moment for £10.

Would the bargin middle size megablocks connect with Duplo then or would that be too easy?

DS has one small lego vehicle which was given to him in a party bag and I built it. Am considering taking it apart and setting him an aptitude test! If you can reaasemble this it's lego - otherwise Duplo.