Taken from GSMArena.com review of the GS2 Plus:
"The new Broadcom chip inside will undoubtedly put up some different benchmark figures, and may even help lower production costs so Samsung might even deliver the Galaxy S II Plus at a lower cost than the original.
BenchmarkPi sees the S II Plus land towards the bottom of the pack in terms of single-threaded CPU performance, but that's expected against mostly higher clocked processors and ones with newer-gen architectures.
Quadrant is an altogether different story, as the Galaxy S II Plus handily beats out the ICS-powered Galaxy S II, and slots in just behind the quad-core devices in our test.
GLBenchmark runs offscreen at 1080p resolution - putting all our tested devices on equal footing. The Broadcom VideoCore IV HW GPU failed to beat the Mali-400MP inside the Galaxy S II, but stayed pretty close to it, nonetheless.
One theory on what exactly Samsung was thinking when it released this device is the phasing out of the old flagship with a newer (and cheaper to manufacture) model. Scaling the onboard storage to 8 GB aligns to this, as flash storage is one of the most expensive components found in a smartphone.
Also, by outsourcing to Broadcom for the chip manufacture process, Samsung would be able to free up its own factories for making more Galaxy S III and Note II SoC's. But what does all this mean to the consumer?
First off, while the Broadcom chip may not be offering a performance advantage over the the Exynos found in the Galaxy S II, it delivers anything but a bad midrange experience for the Galaxy S II Plus, particularly under Jelly bean. Looking forward, the potential cost reduction of the Galaxy S II Plus could make it quite enticing indeed, particularly if the Galaxy S II was to no longer be available.
With both devices still on the market and currently priced the same, however, you'd be crazy not to go with the original Galaxy S II.
The formula that worked for Samsung two years ago still works today, and Jelly Bean has brought some extra value to the experience.
You get the better-performing Exynos chipset and double the flash memory for the same price (there's a 32GB model
available as well)."