The .50 Cal has a lot more of a raw sound to it. It feels natural, no matter how much gain you throw at it.
And....with some maintenance and a transformer upgrade, it can be turned into a monster! :mrgreen:
This amp likes to be loud though before it starts to shine, so if you are planning on just playing it at the house, go for the Express. You won't get the .50 Cal to sound like it should at bedroom levels!
The Express has way more tones inside of it though and is just powerful enough to use with my band when I don't feel like lugging the Heartbreaker around.
I have the 1x10 version which had a crappy Eminence speaker in it that just got flubby and dull sounding at any real volume.
I replaced the Emi with a Weber ceramic 10 VS and now the amp shines!
This amp sounds great at any volume I use it at. The drawback to mine, again, is the 10" speaker. When I use it with the band, I have to use a 1x12 extension cab and the internal speaker just to have any clean headroom at all.
Other things to think about:
The .50 Cal will most likely need servicing. Usually, they need to have the tube sockets cleaned and re-tensioned, pots and jacks cleaned and caps changed to make them sound and work the way they should. Also, I have had to replace the LDR's (things that do the channel switching) in a lot of them.
This is not a bad thing at all, and these are by far one of my favorite amps. It will cost you around $150 - $200 for the maintenance, and you may still need tubes after that.
The Express may still have some warranty left.
If it were me, I would buy them both at that price. Then, use them both for a month and decide which one to ebay and make a little profit! :twisted: