I respond quite well to both Spike and Power Drive, but they are different.
Power Drive used to be sold as a preworkout aid. Then CT and some others saw its benefits as post-workout CNS recovery. Spike was launched and it took over as Biotest's stimulant. Power Drive is now sold as more of a CNS recovery aid. I still use both preworkout, but not at the same time and for different reasons.
Power Drive is less of a mental aid for me. I notice more focus, yes, but it really shines on high intensity training days. Definitely it helps me to increase my loads if I'm testing a 1rm or working in the <5 rep range. It's also excellent for explosive oly lifts.
So Power Drive for me is a strength aid.
The original Spike required more dosage for me to notice an effect. The newer pill form only requires 1 pill. I respond better to the newer pill version: more focus, a calm but determined state of mind in accomplishing tasks.
In the gym you will notice its effects in a more efficient workout with less desire to take the extra 10 seconds rest. You might notice a strength increase in that you're mentally prepared for the task. It seems to have less effect on me in a strictly physical sense: I notice more increase in heavy lifts with Power Drive.
Does that make sense?
Anyway it is excellent for studying and especially for sports.
I'd recommend both. Some respond more to one than the other. Others don't respond at all to either.
And finally, no, there is no crash when it wears off. You simply return to baseline.