Even though the write speed is very low (8MB/s) for any standard express card; but read speed seems to be 18MB/s; so decided opt for this as it can serve as ready boost to my Windows operating system that is running under Vmware Fusion along with storing all my music files. I needed one, so that I can move all virtual machine files to this card; but due to the slow write speed; its hard at this time; and I may need to wait till we get the true SSD performance on Express card.
One funny thing is; Macbook seems to eject the card few hours once automatically; which seems to be odd to me and search does reveal that lot of other people also has the same issue. Not sure if its a bug from Macbook or Transcend.
Anyway, I will wait for the true SSD speed on express cards.