Hey!
I asked the same question about a month ago. Check out the forum
http://www.concertina.net/forums/index.php?showtopic=972Everyone I talked to said that I should pretty much avoid the hohner and spend the little extra and get a Stagi.
I searched around and found a guy selling several brand new Stagi B1's on Ebay for around $150 which was cheaper than some places selling the D40!!! He even gave me free shipping!!!
The B1 is just like the D40 that it's a 20 button anglo. It sounds good (to my untrained ears) and plays really well. The only complaint that I have is the buttons like to stick in at a slight angle and wont pop back out unless I pry them out. I've talked to a lot of people about this and I guess it's really common on the "student" models like these.
I'm really happy with my Stagi knowing it will last a long time.
As for 20 buttons vs 30 buttons, it's only been 2 weeks since my B1 arrived and I'm already wishing I picked up a 30 button. I don't regret getting a 20 button, it would just be nice to hit those notes that I keep searching for.
Congrats and good luck! Keep shopping around, you'll definately find a good Stagi cheap. Oh yeah and welcome to the group! The people here are awesome. So helpful, I don't know if I would have made it this far without their encouragement!
Sean Kelly