And let's not forget that not all SSD's are the same. Some of the very old SSD's are not much quicker than mechanical HDD. So it really depends on how recent your friend's SSD is.
Older SSD's have lower read/write speeds with as low as 100 mb/s, and more recent ones having 400-500 mb/s.
Speed also varies greatly depending on the SATA connection. If it is connected into a slower SATA port the read/write speeds will be adversely affected and you will not achieve full performance.
Edit: I can understand why you'd choose more space. But, if the opportunity ever arises again, I really do recommend one!