Which 15" Cab to get, Ampeg or Hartke?

[OOTB68]

I am looking at getting a 15" cabinet and I am torn between 2. I am strongly considering a Hartke HX15, bassed on its light weight and what seems like some great perfomance for a reasonable price. However, I recently picked up an Ampeg PF500 and I am also thinking how nice it would be to get the matching PF115HE for it. I picked up the PF500 to use for smaller gigs and convenience. My regular rig has consitently been an Alembic F1X preamp (sometimes in conjunction with an SF2 Superfilter) through either a Stewart or Mackie power amp and then on to an Epifani UL310 and Trace Elliot 2x10 cabinet. I have been itching for a 15" cabinet to be able to add a little more variety and depth to my sound. Also, being as it is an 8ohm cabinet, I will hopefully be able to make full use of a 4ohm load when used in conjuction with the Trace Elliot cabinet which is also 8ohms. The Epifani is a weird 5.6 or 5.3 ohms due to the 3 speaker configuration. Does anyone have any suggestions as to which 15" cabinet would be a better performer or might be most suitable for swapping around in different configurations for different situations and experimentation? How do these 2 cabinets comapare? If the Ampeg performs on par with the Hartke, I was thinking it could be the best all purpose cabinet being as it wiould also be the perfect companion to the PF500. Any thoughts out there?