to whoever said ...
F5's if you like commercial solutions
F5s if you like expensive commercial solutions .....
Those with a less bulging wallet may wish to speak to the guys at Zeus Technology (http://www.zeus.com/) who have a lot of experience in the area and a more reasonable price tag.
Contact me off-list and I can give you some names of senior techies there to speak to.
(usual
disclaimer that you should research your products .... it may be that
for your particular application/environment/business model/whatever F5
may be your tool of choice)