imo.....the Express is a very unique animal when it comes to tone controls. It is very capable of delivering way too much of everything, especially upper mids and highs, especially with the extra kick you can get from cranking the contour knob. The up side to that is I think the Express treble knob sounds better than the treble coming from my guitar and pedals if I have my guitar treble turned up all the way. So I ended up cutting the guitar tone and slightly boosting the amps treble and mids. My favorite component of the Express tone comes mostly from the bass knob, but it can get overwhelming very quickly. In short, this amp is superbly capable but very tedious to dial in. Fortunately, the 12 incher is a huge advantage over the 10.
It is hard to "describe the sound" but I can add my two bit suggestions to the list here......
My favorite 2 or 3 speakers by far with the Express amp for use on stage are EV, Weber Texas, and Tone Tubby. These speakers have the complete freq spectrum and will not leave you wondering how to hear yourself when you stand next to the drummer. Love these 3 but note that the EV stands clearly above all the rest. For the 10 I absolutely raved about the Tone Tubby Superboy 10, which is actually a bass speaker, but it can handle anything that Express can throw out, and it doesn't sound like a bass speaker! It actually has a full enough freq response to give you everything you are expecting to hear from a guitar! Superb! I dont know how long EV's take to break in because I've never bought a new one, only used and (as far as I know) original. But once you dial it in there is nothing else like it, especially for an amp of this quality. Honorable mention on equal ground but not my taste would be Weber California and perhaps a couple of the high power Eminences like Swamp Thang for warmer/darker, or Tonker if you like it brighter. But they dont seem to have the "raw and alive" quality down pat like the California has. The California to me sounded like it was made for Strats, which is what I play, but I spend a lot of time trying to make my Strat sound smoother and cleaner than perhaps a Strat should really sound. So I ended up favoring the EV and the Texas over any other Webers. Since you mention a bit of metal in your songbook, I will not suggest the Blue Dog or the Silver Bell, those are more blues and classic rockers sounds.
If you will be playing at home mostly, mostly by yourself for fun, or mostly just for recording, then you can get away with a different selection of speakers to choose from. There are a few speakers that dont necessarily cut thru on stage as well but which are excellent for recording and soloing. Most notable for me was the Weber Michigan, very smooth, very stand up and take every punch you throw at it kind of speaker, and easy to give the sound some extra everything and the Michigan will still remain clean and tireless. If you side by side it with an EV you will quickly realize that the Michigan is smoothing over some rough edges in the sound, it is not a "brutally honest" speaker at all (like the EV is) but if you were to play Webers and only Webers at home or maybe in a straight clean blues band or a jazz or lite fusion band, the Michigan could easily become your new best friend. Rumor is the Michigan is perhaps Weber's least efficient speaker, which accounts for a lot of its smooth sound, so it is a good choice if you are the only guitar in the band and you are not using a ton of distortion in your song list. Actually, the Thames was very similar. I had them side by side and was almost unable to tell the difference. In a 2x12 together it sounded like one speaker only bigger. The 12F150 is supposedly Weber's most efficient speaker, too bad it doesn't have a hemp cone or I'd try it today.
If you want the best for both worlds, EV is the top USDA pick, with Tone Tubby a close runner up. Be careful with buying used EV's, there are a ton of recones out there and many sellers are not in the habit of openly advertising that it is reconed. A lot of them seem to have a "if you dont know what to ask, that's not my fault" attitude. I cant say any of them have lied to me (though I've wondered about a few) but dont expect them to volunteer any info. I've concluded that the best bet in used EVM12L is the ones that came out of Mesa amps and might be described as EV Black Shadow in some cases. EV Force is an option but I think they sound a bit different than the real EVM's do.
I also do not appreciate the V30. As a rule of thumb I would suggest finding a speaker that has little or no "presence peak" for this amp. The Express has plenty of that already. If you try a Tone Tubby you will notice that it is almost impossible to find anyone selling them used. That says something..... they get them and they dont like to let go of them. Must be a reason. New ones take a long time to break in as the cone is said to be more than 50% hemp, very stiff. My best luck with Tubbys has been new ones for $113 from South Valley Vintage Amps. Scott offers great service. He also sells a few Webers. I also notice I have never seen a 12 inch Weber Texas for sale used either. 12 inch EV's are more common probably because they've been doing it so long and there are just more of them out there.
And remember that this amp is extremely impressionable to what kind of signal you feed into it starting with the pickups, pedals, etc. all the way thru to the speaker. I doubt that you can get away from that center cone projection syndrome, every speaker does that in some way. Hope this helps and I'm not making the choice more brain bending than it already is. I have more first hand knowledge with the 10's but this should give you something to think about. Nice thing about EV's also is they have the best resale value if you dont like it. Just keep in mind that you have to redial EVERYTHING and do your darndest to get "your tone" from a speaker before you decide you dont like it, especially the EV's. But if you dial it in and you like it, you will love it!!My current lineup is 1x12 EVM12L, 1x15 EVM15L, 2x10 Tone Tubby Superboy + EV10BX, and 2x12 Tone Tubby + Texas. The Express currently has a Tone Tubby in it, but I think the Texas was my favorite to date. I let go of it so I could raise money for the 2x12. I had a chance to grab a 10 inch Michigan but I left the house and the auction ended while I was enjoying 3D Avatar. Probably wont' see another one of those for a few years, and Weber does not make them any more.
I should probably add that the one Celestion I tried that I liked was the Gold, but it is hard to dial in and will not give you the full range of freq response that one might like to get from an amp of this caliber. Superb when dialed in but it is definitely a Celestion speaker then and not an Express speaker, if that makes sense.....otherwise I am no fan of Celestions.
