Random 4kb reads(with low queue depth) coupled with access time is really where its at. 4kb low queue depth is really dependant on single chip because its basically a case of accessing a chip, reading then the command is sent to access the next bit, so its basically down to single chip speed + access time for each request. Higher capacity drives increase speed on higher queue depth and sequential through more chips per controller, its essentially raid.
Realistically as Sunama said, most people limit big file transfers to hdd's, downloading large video files, installing a lot of games and things directly to an HDD, so unraring stuff is done from and too an HDD. If you are separating most of your large data access to HDD and programs to ssd, then sequential is pretty irrelevant beyond a certain point.
I notice a grand total of almost zero performance difference from a first gen crucial drive with 200mb reads to a C300 with 350mb's reads, randoms didn't change much, nor access time, I can barely tell the difference in real world use, and couldn't really tell the difference between a 64gb indilinx Crucial and 2 in raid 0, nor the 128gb C300 drive.
The limit on hdd's wasn't ever really sequentials, I went originally from a 2xhdd raid 0 setup that would give 200+ sequential read/writes to a 100mb/s read 70-80mb's write slightly stuttery early gen Samsung and it BLEW the hdd's away with half the supposed speed. Ultra responsive performance is access and random performance. There really isn't anywhere to go on access latency as its essentially nothing already, and random performance needs a significant increase in per chip bandwidth and that will still only make a small increase in speed as due to the size of reads and random nature its reading for a smaller amount of time than accessing.
hehe, late, too much caffeine and high(migraine medication not just recreational) means long posts.
90gb WILL be faster but you really won't notice it 99.999% of the time. If you found some really old drives cheap the size/setup might make more of a difference, last two gens, benchmarks, huge difference, real world, indistinguishable.