If you really are as indifferent as you sound, you should pass on this deal and spend your money on something you'll appreciate more. However, if you are leaning toward owning a S&W, you could do much worse. It is a good deal on an iconic revolver as long as it's in good working condition. I suppose the low price is at least partly due to the barrel length, as the shorter barrels are more popular and accordingly more pricey.
You no doubt already have or will hear much ado about the Achilles Heel of the model 66: the "weak" forcing cone. Don't give it any thought, or at least don't dwell on it. The model 66 was conceived as a compromise between weight and strength, and heavier ammo was par for the course when it was designed. It makes no difference with 38 spl, but if you're shooting magnums, stick to at least 14X grains and preferably at least 158 grain magnums; avoid light, super hot ammo like the plague (in particular 125 grain flame throwers), check your timing regularly and you shouldn't experience the dreaded cracked forcing cone. If you respect its limitations, your hand will likely wear out long before the model 66 will.
On the other hand, if that thought of that sort of compromise bothers you or you fancy 125 grain magnum ammo, then stick with Ruger or look for a model 686 with it's heavier L-frame and more robust forcing cone.