Are wheel adapters/ spacers safe?

[jsbihn]

Hey all
I am looking to put a 1-2 inch wheel adapter/spacer on my stock wheels. I figured with a 3 inch key/spacer lift and 38 x 14.5 x 17 that I would need them to clear the suspension. (please tell me if I am wrong).
These adapters are the kind that you bolt to the oem hubs and they have their own studs you would bolt the wheel to

So...
My question is are they safe?
I have heard that some have done them, and others wont.
I would like to heard from both please.
I am not really a hard core off roader so, are they safe? Do they make hubs or parts wear faster?
I will also be doing an alignment after they are done, and most of the suspension and steering components have been replaced with Moog as of this and last weekend

What do you think?