Being involved in a Business that deals in second hand trade ins, I know a fair few people that switch gauges for whatever personal reasons. I do indeed know someone who's brought in there modest OO collection and switch to tt120. Still very early days. But with limited runs if its something that you wanted to do, best get whilst stock is available.

I've done exactly that...

Terrific scale. Unlike most british scales, TT rails are actually the correct distance apart! Modern manufacturing means the detail is awesome. Just that crucial bit bigger than N, but still extremely compact. Over time I see this crushing N. The OO let's-pretend-it's-a-scale boys will be safe, though some of them seem to be panicking already.

Just had my HST 43 arrived today blue and grey and it's fantastic. It looks better than my 00 one which I have both colours. I will be getting another tt120 43 intercity Swallow. You can do 00 009 and tt120 i do.