Well, the price sounds good, assuming revovler is in excellent condition, which it should be.
Blast and flash from a .44 Magnum is dependent on the shooter. I shoot heavy loads often, so the .44 Magnum doesn't bother me at all. Someone accustomed to .38 Special or full size 9mm will find it startling.
As to grips, I prefer the factory stcok grips, or duplicate aftermarket grips. Avoid those rubber grips for a .44 Magnum. They will abrade the web of your hand bloody raw! Also avoid checkered wood or plastic, and stag, real or imitation.
As to holsters, your preference dictates. I don't like shoulder rigs, preferring a good gun belt and Tom Threepersons type holster.
If you are new to the .44 Magnum, I'd advise you to start out with mild loads, or .44 Specials if you should not happern to be a reloader.
As to the 7 1/2" barrel, it is, in my opinion, ideal for the .44 Magnum, as it puts the muzzle blast a little farther from you, and the weight dampens recoil to a greater degree.
With practice with the .44 Magnum Ruger Super Blackhawk, I believe you will find it to be one of the most accurate and fun revovlers to own.
Bob Wright