I keep hearing the 'suspension gets in the blood in a few hours' comment, but in practice I question this. I found it to be much less predictable. It is apparent that the test base forms a 'crystal depot' in the muscle, and for some reason the dissolution of this depot is not that easy to pinpoint. I have personally found that it can 'sit' in that depot for days and then release itself in 'spikes', and other times it seems to rapidly disperse. Pain levels also vary, which probably is due to the same unpredictable depot effect. Some injections don't hurt much at all, but other times it can hurt like hell for a week, like there is a 'walled off' chunk of sharp crystal sitting in your muscle.
At least with prop you know that the delivery should be reliable and at least somewhat prolonged when it does deliver.
I much prefer the prop.