In techincal terms,
If you compare the system designs of both systems, the Genesis is far better designed spec-wise for a 1988 machine, vs. SNES for a 1991 machine. A large part of that was because of the insisting that the SNES have a PCM-based sound chip ( SPC-700) instead of a hybrid solution like a YM2151+OKI6295/ YM2610. As a result, the SNES had to cut back in the CPU power, the amount of RAM for different areas, and backwards comptability to keep the price down.
Both systems had terrible default sound drivers, meaning that third- parties had to create their own sound drivers if they wanted to use different voicings/samples from the defaults. Good examples of this are the FFIV-FFV-FFVI OST's for the SNES, and Thunder Force II-III-IV for the Genesis.
When it comes to games, I think the SNES overall has top tier games in certain genres such as RPG's, strategy,action-adventure, and platformers, while the Genesis had better sports games, arcade games, and shmups. One of Sega's tactics at the time was to make more games, which were usually B-tier quality ( Sonic Spinball, Kid Chamelon) to compete against Nintendo's A-tier games that came out less often. More games translated into more overall sales, especially once Sonic started to help sell Genesis systems.
Phantasy star IV is up there for an rpg of high quality.
I think part of that is Sonic was Sega's mascot. 
With Nintendo staring out with Mario front and center and Sega bringing Sonic on board after the fact they had to heavily advertise and put him out there.
He was their (very effective) Mario killer.
Other than the titles already mentioned what are some of these lesser known Genesis killer apps you speak of?
I'm not trolling. I have 3 Genesis consoles, 2 game gears and over 80 games for the Genesis.
None (other than Sonic series and Streets of Rage) really stand out to me.
Many here keep talking about the awesomeness of the game library. So I'm not trying to argue that.
I really just want to know what I'm missing.
This is exactly what I mean most people who are a nintendo guy with a sega only talk about sonic and streets of rage and or golden axe or altered beast. Definitly not the greatest games so stereothypical and people saying so many sport games. People are just missing the picture when there is no famous mastcot mentioned in the games.
I mean the game the mentioned above are easy to come by and the better known titles on the sega are pretty hard to come by but not that expensive by all means when comparing to nintendo.
Just some examples of what you are missing
The sega is a system of shootemups musha truxton thunderforce phelios raiden trad etc.
Arcade games: strider, second samurai, mega turrican better than the 2 super turrican games on the snes by far. super turrican 2 was particulary bad. splatter house series outrun.
Platformers/ run and gun castlevania bloodlines, rocket knight adventures, sparkster shinobi series contra hard cops, gunstar heroes.
Rpg's phantasy star series IV is the best III is the worst, shining force series, crusader of centy
There are way more games, I just hate it when people don't see this awesome games in the library
I have seen more people with 80 games for a console but quantity does not mean quality since allot of people have allot of filler titles wich are not worth playing. There are allot of crappy games on the sega but same goes for snes.
Also I do see you have some nice quality games in the collection for the sega.
Have you ever tried playing shinobi III castlevania bloodlines turtles hyperstone heist, contra, gunstar heroes, ristar or rocketknight?
All quality games but few in that list are one of the best of the system I'm suprised you only find the sonic and streets of rage games to stand out when you have some awesome games in the collection some wich are the best for the system. I'm curious if you have ever played one of the above titles, if not give them at least a try especially shinobi III.
If you don't like all games mentioned above than the sega ain't for you aside from the sonic titles with respect since everyone has their own taste and these are the kinda games sega has to offer.
