Spent a couple hours selling type 9's and modules back to dalton station, got into a python. Did some testing with it, here are my overall impressions:
A python fitted with A-type thrusters on the beta server flies with about the agility of a type-E thruster python on the main server. My maximum speed while boosting was around 310 m/s on the beta server with type A thrusters. The type-E thruster python on the main server gets around 330 m/s boosted.
Took the python into a bounty hunting site - performed well. The reduced shields are noticeable, but not terribly detrimental.
I'm not the best pilot ever, but I tried to get some pvp action with the nerfed python. All told, I managed to get 4 1v1's: 3 Against vipers, and 1 against a cobra. I have no idea how good or bad the respective pilots were, so anecdotal evidence is anectodal. My loadout was pretty mediocre: Three Gimballed Class 3 Pulse lasers and Two seeker missiles. Mostly A type mods fitted, A6 shields, shield cells, etc.
Of the 4 engagements I managed to kill 1 viper and the cobra (cobra died really fast), in both of the other engagements the viper managed to disengage. All 4 were using chaff, so had to use my pulse lasers un-targeted. The only bit of fancy flying on my part was going FA off and full reverse to keep them in my sights as much as possible (like I said, I don't claim to be the best pilot ever).
One of the vipers tried to dumbfire me to burst down my shields - didn't end up doing much.
The impression I came away with is that while the nerf is noticeable, the python is still a very capable ship. Having flown the imperial clipper and the asp extensively, I rather doubt any of them will surpass the python in the combat role. Hell, the asp is just a fatter, slower cobra for purposes of getting shot - I know I wouldn't want my asp to get caught in the sights of 3 large weapons.
Anyway, just my 2 cents from having actually flown the thing on both servers.