Replacements are a good option, but I would recommend only buying the ones say they use the same high quality cells like the ones found in your OEM equipment. Example Samsung/Sanyo/Panasonic/Sony/and LG are makers of the li-ion cells found in your original battery from the factory
If the replacement battery reseller is selling a battery that uses good cells they are going to state it. If they don't then you don't want that battery period!
Also, once you find a someone that is selling a battery that uses quality cells, you need to know what the capacity rating mean. Here is how I translate the capacity numbers into something meaningful that most understand.
4400mAh 6 cell batteries =
older technology/ low capacity...but inexpensive! Expect about 1-2 years of service life with about the same battery runtimes as you previously had from your original battery. (Most current laptops still have batteries that are rated at 4400mAh - to 4850mAh)
5200 mAh Batteries =
Used by many OEM's and last about 2 years. Capacity is good, meaning you should be able to run a decent amount time unplugged as well.
5600/5800 mAh Batterie
s = State of the art advanced Li-Ion as of 2011. Capacity is very high and so is service life. Expect 2-3 years between replacements and extra power that you never had before to run unplugged longer! As an example here is the one I bought for myself recently http://www.safebatteries.com/dell-31...k-5800mah.html
Hope this helps,
Oh, one last thing If the only thing stated about the cells being used are that they are "Grade A" then LEAVE FAST! This is a pet peeve of mine. Stating the term "Grade A" is a misleading term for consumers. "Grade A" is an actual term, but it is relative to each and every manufacture and does not
imply anything about performance or quality to the consumer. Example, some no-name factory is selling "Grade A" cell at x price. That same "Grade A" cell may be considered "Grade C" or worse by Panasonic or Samsung! It just means they are the best cells that a particular factory can make.