i just used ATTO disk benchmark to test the speed of my mushkin enhanced chronos deluxe and got these speeds. i never expected to get the full advertised speed but i did and more! but is this program accurate? http://imageshack.us/f/515/ssdspeed.png/
Also, don't get disappointed if it starts to slow down after a little while. SSDs have this "golden time" when they first get installed. Essentially until each cell gets used you get faster performance. Afterwards, you experience a mild performance drop. But it's a single step, not a continuous degredation. Should stay equal or above the advertised speeds.
None the less, Dereck47 is right. Some times you just get lucky. Bask in it if you are!
Most manuf use ATTO for their published specs so should get close to (± 10%).
That said ATTO is a poor choice for benchmarking an SSD as it uses highly compressable data - far from real life - in use performance for a OS + program drive. ATTO would be a good benchmark if the SSD is used as a storage drive and working with LARGE file types such as dvd VOB files (typically 1 gig), Bluray files (10->40 gigs), large spreadsheets, Large number of jpeg/bitmap photos (10+ meg/photo).
Myself, Skip atto data in reviews and only look for PCMark vantage and as a 2nd choice AS SSD which was developed for SSDs. AS SSD is what I use on my systems (PCmark Vantage cost money and is rather large). AS SSD is not perfect as it uses Compreesd data, but does come closer to mimicing real use than atto.