has anyone get any underground ernie merchandise? is it any good? in particular trains - do i go for big plastic ones or small die-cast ones??

[beautifuldays]

ds has decided he wants underground ernie for christmas - do i get the plastic pull back trains and an underground ernie track for them or do i get the (possibly more robust) die-cast metal treains and some take along thomas track? does anyone already own either of these sets? are they any good? thanks xxx

can anyone help?