If N43SL has Nvidia Optimus, then it'll probably have better battery life...
We're not too sure whether it has it or not...
We're not too sure about the battery capacity as well due to the confusing details in brochures...
But I think A series has higher battery capacity, in which it'll offer more battery life
Updated: The N43SL says it probably have Nvidia Optimus since 2 GPUs are detected

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Added on May 13, 2011, 10:42 am

14"
Acer Aspire 4750, i5-2410M + Intel HD3000@RM1999
Acer Aspire 4750G, i5-2410M + Nvidia GT 520@RM2249, 3 years local limited warranty
Asus A43Sj, i3-2310M + Nvidia GT520M@RM1999 (2 years international warranty)
Dell Inspiron 14R, i3-2310M + Intel HD 3000@RM1949
Inspiron 14R, i3-2310M + AMD HD6470@RM2149, Free 2nd year warranty: expires 12 May
Inspiron 14R, i5-2410M + AMD HD6630@RM2349, Free 2nd year warranty: expires 12 May
HP Pavilion G4, i3-2310M + AMD HD6470@RM1999
Lenovo G470, i5-2410M + Intel HD3000@RM1999
Toshiba Satellite L745-1049U, i3-2310M + Intel HD3000@RM2099, 2 years warranty (1st year global)

If you game, then get those with dedicated GPU (Not Intel HD3000), if you don't game, get those with i5-2410 CPU 
The Microsoft Office will be trial version only...