I have upgraded to the CS 500 four or, five years ago, since then it has been replaced through a recall and have just replaced the battery and not sorry about it. As a compact unit it packs plenty of power, easy to service, and speaking of service, communications with reps or making orders has been outstanding. As for the business end of the unit, the power recepticals are well identified and there is enough to go around. Over the years I have had the experience not only in using APC equipment, but installing and recommending this product. A very wise and in the long run a money saver