Not so nice. Because wings have high pressure underneath and low above, there is a movement of air between the two. Quite a lot goes around the wingtip creating, because of the movement of the wing, a swirl of air. I think I recall that this swirl off both wingtips creates a local downdraft of air affecting the aeroplane as it moves forward. Thus the aeroplane is flying through this downdraft, or continually having to 'climb' through it (by making the incidence greater), thus increasing drag.
I can't think vortex production is in any way beneficial. It shows leakage of air thus reducing wing efficiency.
A pretty good article on vortexs is here:
www.chirp.co.uk/air/Docs/GASSL15B.doc
The second statement does not sound right, but.......standby for incoming!......