Hi Silver Fox,

As a general rule of thumb any decent Scarifier will also Aerate to a certain extent depending on how well it is manufactured. The old Qualcast and Black & Decker models used to use "spring tine" scarifiers which worked only as a scarifier and not very well in my opinion. Modern Scarifiers normally use a primary drive spinle which has several blades mounted vertically to not only remove the moss and thatch but also to cut in to the sod and improve aeration and gradually reduce the problem year on year (distribute sharp sand or similar after using the machine)

Some good brands in the electric stable (which also have good after sales service for spare parts etc) MTD Lawnflite, Al-ko and Mountfield.

You will often find collection bags are sold as an optional extra for these type of machines. Scarifiers are not very good collectors and I would always recommend using a Rotary Lawnmower after the scarifier purely to collect the debris. They work on vacuum and will effectivly hoover up anything left lying loose in the lawn.

Hope this helps