Ash said me that the PLs can be more efficient than the energy saving CFLs, even if the PLs operated with a preheat magnetic ballasts and the CFLs operated with HF electronics.
The reason is because that PLs have simpler shape than the CFLs and this results in more light release and therefore more lm/w.
Because of this, when my Osram DuluxStar 8W/827 in my spot, will end its life, i will probably replace the spot with a PL-C/S fixture with an electronic or even preheat magnetic ballast.
Also, PLs (In Israel at least) are more expensive than energy saving CFLs, as in CFLs the low cost have higher position than the efficiency and the lifespan of the lamps.
At the same time btw: Why i brought my first CFL to my table lamp, when i was still lived in my mother home (At the end of the 1990'), i wanted to buy an Orion adapter and 9W PL-C/S, but my mother thoguht that this is bluky, huge and ugly, so i had no choice but to but an Osram Dulux EL Longlife 15W, through this was in the era of the non chinese very high quality CFLs and the lamp was perfect still.
In that era, i didn't knew of the electronic ballast at all, so this was the first meeting of me with a HF ballast.

PL has better shape to dissipate the light, which is why more light actually gets out of the lamp compared to CFL

The PL-S 11W is very good example. I tried to compare it to 75W incandescent, and the light output is about the same. Which means allmost 7x lm/w compared to incandescent, or i'd guess about 5x if you take in few watts for magnetic ballast

The 15W CFL that is being sold as "75W equivalent", does not reach real 75W incandescent light output, therefore is less efficient than the PL

PL-D have in part the problem of CFLs since for each tube there are 3 others obstructing it from 2 sides, but is still much better than CFL - In PL-D each tube is about 90 deg hidden, in tubular 3U CFL it is 120 deg hidden, and in spiral you also have the uneven phosphor coating problem



Based on my experimenting with PLs and CFLs, evaluating light amount by eye

It is valid mainly for the PL-S 11W, what consume about 15W with the ballast losses and deliver 900lm of light, what mean about 60lm/W, what is about the average selfballasted CFL (but way more reliable and robust).
For lower wattages when operated in "solo", the performance would be worse, as the ballast losses are the same or even increase, so PL-S9W would consume with the same ballast about 13..14W, what make it a bit less efficient 600lm source. Even worse for lower wattage.

But when you use two lamps in series, the ballast losses would drop and divide between these two lamps, so with 2*PL-S9W you get 2*550lm for about 19W of power, while with selfballasted CFL's you are at about 22W (I expect you need two light sources, so using one 1100lm lamp is out of question).
Same with PL-S7W

PL-S5W work even in triplets (improving it's economy), but I didn't tried it (the limit is the starter trigger voltage; F4T5 woked in a series quad, but only with manual start)...