NOTE: I have not heard the Doge 8.
The ET3 is a nice tube Pre Amp for $2500, but is much improved in the ET3SE with the Teflon Caps. The ET3SE is $4000 MSRP - you can probably get it for $3600. Getting the SE upgrade later on will cost a little over $2k. So if you are going to get the ET3, save up another few hundred and get the SE version.
Tubes: Tube replacement cost will be higher in the Doge due to the number of tubes.
ET3 only needs ONE tube - 6922/6DJ8/7DJ8
Doge 8 needs EIGHT tubes - 4 12AX7, and 4 12AT7