My opinion is similar to Deadeye. Furthermore, I liked the SG so much, I just got a Supet NT. The convenience of being able to play an original cart on a modern tv and have no loss in quality out of the box is really a great value.
Also, I personally think the Mega SG picture and sound put Genesis games on a different level than before. The Super Nintendo, I don't notice much of a difference between the original console and the analogue. I think Sega games look and sound much better.