Glass build platform is the way to go!

[curious aardvark]

well my issues were definitely: 'not-level' bed based.

Printed out 4 things without raft yesterday, at reasonable speed too !
Might not sound much to you lot, but it's pretty amazing to me :-)

It didn't like the the vacuum cleaner adaptor - but I could see that was purely down to the way makerware slices cylinders. Ie: It doesn't go round in a full circle, but goes round to one point, then reverses direction to the same point then reverses again. It's why you get a seam. But because of this the first layer didn't go down properly, it pulled the edges of the first circle up on the reverse and just left a permament gap.

But the electric carpet sweeper handle worked perfectly ! (even the sample prints).

So I suspect it doesn't actually matter what material your bed is made of - as long as it's 100% flat and level.
And as far as I can see - no flashforge comes with a perfectly level bed. (or indeed any other make - not level beds seem to be at the crux of a lot of people's problems with 3d printers)

The thick glass bed sounds good. But I can get aluminium beds for free - no contest. Plus just an extra 3mm means I don't have to piss about with shims for the zaxis.

I'm tempted to put a layer of kapton on the reverse side of the plate. To give me bluetape one side and kapton the other so i can just flip the plate to change :-)
The blue tape sticks really well now I can calibrate the machine properly.
So tempted to give geoffs favourite kaptoon a go. I've got a huge bloody roll of the stuff - so might as well try it out :-)