No, I'm not a CSP officer till now, I am going to appear for my 1st attempt in 2010. But one need not be a CSP officer, to know the basic information I have provided me in my post, besides I do have some friends and relatives who are DMG & PSP officers.
I would like if any of the members could "justify the obvious about who enjoys 'far more powers'"
The reasons due to which I am constrained to believe that PSP is a better choice than DMG is that though admittedly DMG officers do hold some key posts after getting into BS-20 or higher(only 20% of these senior officers get these 'key posts', while rest remain posted at 'khudde line' posts), but before that, it is not wise to compare the powers of DDOs, DOs, SO's. and Deputy Directors with ASPs. Restoration of executive magistracy is not in sight but PSP will remain the better choice even if the executive magistracy is revived, due to these reasons:

1- During devolution, though DCOs have figurehead nazims over them, they do not have much influence of MPAs and MNAs on them, at least directly. When the Nazims will be gone, the influence of MPAs and MNAs will increase in the day to day affairs of DCOs.
2- Currently, DCO signs the ACRs of all the EDOs, which gave him extra control over them, but after the restoration of divisional directors, Directors of the concerned department will sign the ACRs of the EDOs.
3- Now, All the funds of the district government are on the disposal of DCO, but once the LGO is abolished, these funds will go in the hands of provincial assemble, and funds will be allocated to the concerned departments at the provincial level. Hence this monetary control will be taken from DCOs.
4- The Police will not come under the sway of DMG until the Police Order 2002 is not amended.
5- Even if some still consider the posts of ACs and DCs better than ASPs and SPs, it is imperative to note that roughly only 50% of DMG officers are posted in field. The remaining 50% are posted in the secretariat, as Deputy Secretaries, Additional Secretaries, and other such posts. And the post of SP of any far flung area is far better than that of Deputy. Secretary, of most of the departments such as Social welfare, Special Education etc.
6- In PSP their is certainty of your power (at least to some extent): once you are SSP, you remain SSP, no matter where you are posted. While in DMG one day you are DG, Inter-Wall City Planning- a post of no significance at all, and the other day you are posted as Commissioner, Rawalpindi (As was the case of Dr. Hasib Ather, current Commissioner Pindi) or one day you are DCO, Lahore, and after remaining OSD for 9 long months you merely get the position of Secretary National Fertilizer Corporation. (As was the case of Mian Ijaz).
7- Lastly, their is a certain charm in wearing uniform, having gun men with you most of the time, receiving salutes of the juniors, and above all holding stick in one hand, and the gun in the other, which DMG certainly lacks, at least in the initial 15 years.

These are my observations, and everyone has the right to disagree with them. If you think their is any flaw in my observations then please point it out, i'll certainly appreciate that.
Disclaimer: I do not tend to disgrace the prestigious DMG, I personally believe that DMG is far better than any other group except PSP.

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Absence is to love what wind is to fire: it extinguishes the small and enkindles the great – Comte de Bussy-Babutin