Has anyone tried on of these on thier Amiga?

[Tripitaka]

Yes you do LOSE colors when displaying AGA on a 16-bit display.  In fact, over 99% of all the colors are LOST.  They are GONE.  Eradicated.   Looks like crap.  Utterly useless.

Well put ChaosLord. Remember folks for each bit lost, your down by half the colours. That's colo-U-rs dammit, f'ing spellchecker, I'm British..... sorry, getting a bit side tracked on a rant just for a mo...anyway, yes , half your colours, 8 times over, and as the man above says, you've lost most of them.

[Tripitaka]

This is just an extreme representation.

You don't "loose" colours, they round to their nearest neighbouring colour. AGA only has 256 palette entries. It is unlikely that games will choose all 256 entries to be shades of red for example.

But if they did, subtle shades are lost through rounding errors and are displayed as their nearest neighbour.

True to a point, but keep in mind that even if only (for example) 3 shades of red are used, the chances are that even the loss of one of them can look real bad. Try drawing a circle in a paint package with a set 4 colour palette, white, red and two in betweens. Now edit the palette so that the two in betweens are the same colour by altering one to make it match the other, you'll see what I mean. It's not nice and it's not just a loss of subtlety.

[Tripitaka]

On some games, true, you'll barely notice, on others...yuck! It all depends on how the colours got used in the first place. as a general rule, lots of strongly different colours will be OK, subtle graduation will not. Truth is, I can't tolerate any loss of tone, hue or saturation in any way shape or form. I've done a lot of digital remastering (mostly martial arts movies) and I notice these things. I'm the guy who cringes when someone watches TV in the wrong aspect ratio or, god forbid, doesn't even bother doing the set up with proper colour bars. I also calibrate my printer and scanner to my monitor ...
... maybe I'm a little anal about these things but hey, we all have our quirks.