I have never used what I believe are known a "root trainers" - I have
previously just used seed trays with cells in.

Do people use the seed trainers? - I can see it would be an advantage to be
able to open them to remove the root balls of various seedlings. (I've just
transplanted some tomatoes into 3" pots and for some reason struggled a bit as
the damp compost came away from the seedlings as I removed them from the
ordinary plastic seed cells - must have been the compost as I have not had the
problem in previous years)

So: do people use them - are they worthwhile - do you use good quality ones
which can be used year after year - or just get thin cheap ones which can be
thrown once used?

(I can see an advantage in growing seeds in coir - as I guess there will be
less root disturbance when transplanted - do people do this much?)