Whole different beast. The Hagen might be my favorite Diezel. It's more in the hi-fi camp than the Ecstasy, but the tone and flexibility are incredible. I only had the chance to try a Hagen at Guitar Center, and for a long time the VH4 was kind of the king of Diezels in my mind. However, what first blew me away was the clean channel, then as I went through the drive channels, I was blown away. It's hard to put into words, but I just really liked the tone.
Some people say the Ecstasy 101b has a mediocre clean channel. I think it's good, but the Hagen has a better clean channel in my opinion. It's just more fun. The plexi mode of the Ecstasy is something the Hagen can't do. It can do tones like in the blue channel of the XTC gain-wise, but it's a different feel and tone. To me the blue channel of the Ecstasy needs some volume to get real good, but the Hagen gives up a lot at any volume. The EQ of the Hagen is better than the Ecstasy. Little tweaks go a long way. Anyway, the Hagen channel 2 is just as badass as the channel 2 blue of the Ecstasy.
Where the Hagen and Ecstasy both excel is on channel 3. Hagen's channel 3 kind of makes you wonder why there's a channel 4 - until you get around to playing with channel 4. I like channel 3 a bit more than channel 4, but if I owned one, that might change. It's just the quintessential Diezel distortion flavor.
Lots of great things to say about the Hagen. The short time I spent with it left an amazing impression on me. That being said, there is something very special about the Ecstasy channel 3 red. Like the Hagen channel 3, you can just sit and noodle on it all day long.
It's hard to say and I won't recommend one either way because they're both incredible. The Hagen is a special amp and I wish I had one. The Ecstasy is very special, and I miss the one I had very much. You get MIDI and all the other features with the Hagen, but the Ecstasy doesn't have all that. However, there is nothing that can replicate the Ecstasy sound. It's such a good sound. If I had to rate each amp on a scale from 1 to 10, I'd make the Ecstasy a 10 and the Hagen a 9.9 for tone. Likewise, if you compared features and flexibility, the Ecstasy would be a 7 and the Hagen would be 11. Tonally, the Ecstasy is very flexible even though it's 3 channels compared to 4 on the Hagen.
Hope this helps.