Buying an SSD was a huge disappointment for me. Programs were not "almost instantaneous" but just 2-3 times faster to load if there was a difference at all. So OpenOffice took 3 seconds instead of 7, not worth the huge price difference for me. Compiling is CPU bound, I noticed no mentionable difference there. It might be worth it if you use a "bloaty" OS with virus scanners and indexers running or have specific use cases where very fast access is needed, but for a lightweight system the difference is neglible. The only real difference I actually
noticed without looking at numbers was that after startx the XFCE desktop was ready before the monitor did its resolution switch. Lots of random reads in that process I guess. From a HDD it takes a couple of seconds (once per day...).
I returned it. And before some is implying I am dumb: Yes, I had a fast and quick SSD and my system was setup to use it well.