Welcome Neo,
ditto what mike said, basically there's no substitute for aperture and the GS dobs certainly represent the most bangs for your buck on offer. Regarding astigmatism, one eyepiece manufacturer, Televue, offers correction lenses for some of their eyepieces. TV eyepieces (and products in general) don't come cheap but are excellent quality. Here's a link to the televue site describing the
DIOPTRX™ eyepieces.
http://www.televue.com/engine/page.asp?ID=259 If you have the money it would be well worth going for quality eyepieces right from the beginning as you will find after a very short period of time that eyepiece selection is of primary importance
. 