Bialetti Mukka Espresso Machine

I bought two of these last year.  Gifted one to my daughter who returned it after several frustrating tries at making capuccino.  I had better luck with mine with only occasional mishaps due to poor seal between the two halves of the unit (no seal-no work).  Put it up though until just recently when I tried again.  This time I had a great seal but the frothing valve failed to operate.  When the safety valve started whistling, I removed the unit from the heat and taped gently on the valve hoping it was just a little bit stuck.  The valve erupted spewing hot water in a geyser all over the stove.I contacted the vendor (who told my daughter they had lots of returns). I'm an engineer and, although I understand perfectly the principles of the unit's operation, I consider it to be at best unreliable. At worst, hazardous.