http://www.vfs-uk-ph.com/additionalservice.html#1
Have a look on here, the VFS website tells you the fine detail. Basically you pay an extra 1800 pesos for a slightly more comfortable appointment. You can book with a minimum of 24 hours notice and select a time of day that is convenient for you, there are free refreshments etc etc and you get personal attention as soon you arrive. My wife had to travel in to Manila from Cavite on several jeepneys / trycycles etc etc with a parcel that was almost as big as she was so I paid the extra for the convenience for her. It was all done in about 20 minutes. Yes it is an extra 1800 but not so much considering all the other financial outlay. It doesnt give you any priority in terms of the processing, just in terms of the submission of the application.