aPVP (alpha-PVP) vs. MDPV comparison:
**These are two very similar chemicals in structure, based on pyrovalerone and resembling non-identical twins in their nature, or a "female" vs. "male" mallard duck... however, they both walk, look and quack like a duck, not a duck/crow (as an example) **.
Also, my qualifications: Regular and in-depth experience with MDPV practically since the day it came out in the early-mid 2000's, and a recent introduction to aPVP via a well-trusted and reliable source.
MDPV (appearance): Powdery white-to-tan.
A-PVP: Clumpy tan to dark tan.
MDPV (odor): Mild "pyrrolidine" type odor (like smelly sweat-socks).
A-PVP: Heavier (moderate) "pyrrolidine" type odor.
MDPV (solubility): Dissolves in H2O with difficulty, mild "pyrrolidine" type odor in solution.
A-PVP: Dissolves readily, heavier (moderate) "pyrrolidine" type odor in solution.
MDPV (smokeability): Vapes somewhat uncleanly, mild to moderate harshness/odor.
A-PVP: Vapes very easily/cleanly, moderate to heavy harshness/odor.
MDPV (onset and duration): Slow to medium onset of effects, lesser dosage needed, greater duration.
A-PVP: Rapid onset of effects (all tested ROA's), 1/4 to 1/3 greater dosage needed, lesser duration.
Summary (useful info): a-PVP vapes better than MDPV, but is harder on the lungs and harsher. Effects come on faster, but last a shorter period of time and more is needed than with MDPV. A "rush" is possible/likely with a-PVP (particularly if smoked or injected), and unlikely with MDPV.
The "highs" are otherwise quite similar -- plain old NDRI (norepinephrine/dopamine) reuptake inhibition and stimulation with varying/unpredictable euphoria, an increase in sexual tendencies and unpleasant tweaking at higher dosages.
APVP "feels like" a cruder, harsher and less sophisticated (but faster-acting and smoother burning) version of MDPV. MDPV is like "high end/fancy/fussy" and aPVP is "low end, poor man, easy-going" version of the same thing.
Given the faster onset and shorter duration of effects, it is possible that a-PVP will be more compulsive than MDPV via rapid onset ROA's (smoking, slamming), but it may take longer to take hold and have an easier/shorter comedown when the user regains willpower. Vapers may experience lung damage/pain with a-PVP (temporary, most likely, but who knows). It is likely (from my research, including contact with a professional source that suggests it) that a-PVP degrades/loses potency substantially faster than MDPV, whether in solution or not, and so care in storage is more of a factor.