Vandersteen 5a's - an upgrade from Vienna mahlers?

Mikej, Have to totally disagree. The tilt back is one of the most important aspects. If it doessn't make a profound difference in your system, you are probably suffering from some room reflection that are masking some of the differences. The window is really not as big as you think. Talk to Richard V. if you don't think tilt is important.
The other aspects get bass correct and the soundstage focused. Tilt gets the integration correct.
I can change mine with a 1/4" difference. It begins to lose high frequency focus. There's one spot where you don't have a question it's right.

i have a healthy respect for vandy, but i don't think its a clear upgrade.

I have finally taken the plunge. . . retired my Maggies IIIAs and just received a brand new pair of Vienna Mahlers. I have now started a thread to chronicle their break in and discuss Mahler related stuff. See you all at:
http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1195845334&openmine&zzGuidocorona&4&5#Guidocorona

With respect to the question of the 5A's bass and dynamic capability: The 5A's have a dynamic advantage that outweighs any potential limitation due to 1st order crossover slopes and that is their active push-pull woofer. No passive speaker can begin to move the amount of air with the level of control and agility that the 5A's active subwoofer does, especially when properly eq'd for the room.

Passive bass from a conventional driver with a single motor sounds dynamically soft, round, and blurred by comparison, even aside from other compounding issues like a ported enclosure. Even Vandersteen's own otherwise excellent 2Wq subwoofer with its more conventional drivers cannot come close to resolving bass information like the 5A.

I sell Vandersteen and Vienna (although not the Mahlers).