How do the latency systems work on SSD's?

So, the other day, I bought an Intel 510 120GB and while I was purchasing it the cashier told me that it was a crude choice and that I should go with any other SSD's. I was astounded in hearing this and I asked him why? (I assumed he was like any other sales associate trying to make me purchase a more expensive product) And he told me that the Latencies on the Intel slows it to the point its useless, and that the delay on the SSD was close to 0.9. I then compared it to a OCZ Vertex 3 and he said that compared to the Intel OCZ would beat it at a rate in which I could feel it, due to its 0.01 delay, and that when transferring files from one location to another the delay in Intel is Massive.

So what exactly is this sales associate talking about? I didn't get a chance to talk to him about it in full detail because of the line up but he is correct in anyway?

 

The access times on the Intel 510 aren't top notch, that's true. The numbers he gave you were wrong though. See here: An early look at OCZ's Vertex 3 solid-state drive - The Tech Report - Page 4

I don't believe that it would be noticeable.

"when transferring files from one location to another the delay in Intel is Massive."

Actually the Intel beats the Vertex 3 in most file copies, see here:
Crucial m4 256GB SSD (C400) Review - File Copy Tests

 

TR nailed it, the latencies for all the SSDs on the market now are excellent and completely outclass spinning platters.

Some of the differences between SSDs approach limits of certain benchmarks to the point where margin of error of that bench might be very significant, especially the 4k random charts I've seen.

Same goes for IOPS, there are differences between SSDs depending on usage etc but they all put hard drives and even arrays of hard drives in a completely different (lower) class.