After researching this for awhile, I can not seem to get an appropriate response on the main differences between the two. I hear alot of positive things about both, but the twin reverb is twice the price of the deville.

Whats the dealio here? What matters for me the most is the clean channel and response to pedals, overdrive channel is irrelavent. Is it just because it is made in America?
"The future's uncertain, and The End is always near."
-Jim Morrison
The twin reverb will have to be veeerrry loud to get any sort of break up, and a pedal will only push it so far. If you want clean, then go with the reverb. If you want some overdrive, go with the deville and buy an OD pedal.
Traynor YCS-50>EHX SMM w/ Hazarai>EHX DMM>EHX Holy Grail>EHX Small Stone>EHX Big Muff PI (NY)>EHX Pulsar>Ibanez TS-9DX>Echo Park>Ibanez Vintage Tubeking>Fulltone OCD>Zvex Fuzz Factory> Roto-Machine>Fulltone Wah>MJM London Fuzz>Fender Strat
I like to think of myself as UG's resident Twin Reverb enthusiast

Anywho, you will find no other amp that takes pedals as well as the Twin. You hear what the pedal is designed to sound like. I use either a Keeley SD-1 or an OCD and can push the amp into lower Marshall gain stages at reasonable volume. With the volume on about 8, I can get plexi tones (with the OCD/SD-1).

As for cleans, these are the best in the business.

You may want to change the speakers to cut down on the icy-ness of the amp. I like the Eminence Red White and Blues.

EDIT: I dont suggest ever setting the volume on 8.
Go to a shop and try them both out. The Twin's louder and has a lot more clean headroom but the Deville has an OD channel, which isn't too good. They'll both be hard to carry though.
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Fender Strat/Tokai LS80>few pedals>Orange Rocker 30
Just like stated before the twin is clean handles pedals great. Look at my sig what I am using. They all sound great thru the twin. I just run an eq to take away the brightness.
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1971 Pro reverb
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the Deville has 4 - 10s doesn't it? That will account for some tonal differences