SEL18200 maybe more expensive, but then the AF is "SSM-like" (better than SAM, according to reviewers) ... so you can't compare it with SAL75300 with in-body AF. There are also some other differences as well, not just the AF.
Personally, I'd rather wait for the rumored SEL55200 ... at least it should be similar to the kit lens SEL1855, or hopefully better IQ/performance.
Support for the autofocus function with A-mount lenses
The following SAM and SSM lenses are supported*:
DT18-55mm F3.5-5.6 SAM [SAL1855]
28-75mm F2.8 SAM [SAL2875]
DT55-200mm F4-5.6 SAM [SAL55200-2]
DT30mm F2.8 Macro SAM [SAL30M28]
DT35mm F1.8 SAM [SAL35F18]
DT50mm F1.8 SAM [SAL50F18]
85mm F2.8 SAM [SAL85F28]
Vario-Sonnar T* 16-35mm F2.8 ZA SSM [SAL1635Z]
Vario-Sonnar T* 24-70mm F2.8 ZA SSM [SAL2470Z]
Distagon T* 24mm F2 ZA SSM [SAL24F20G]
70-200mm F2.8 G [SAL70200G]
70-300mm F4.5-5.6 G SSM [SAL70200G]
70-400mm F4-5.6 G SSM [SAL70400G]
300mm F2.8 G [SAL300F28G]
* With an A-mount lens attached, the autofocus speed will be slower than when an E-mount lens is attached. (It takes approximately 2 to 7 seconds). It may vary depending on the subjects or brightness of the shooting environement.
yea it would be perfect if they can come out a firmware or better adapter that makes A lenses AF as quick fast E mounts on NEX..
This should push up the sales by a mile. but well.. guess it wont happen. Since Nex system are suppose to be small.