My personal opinion is that Class B is good enough for pleasure vessels. If you ask, I won't be able to technically defend that assertion, but all the same, it works well. The only situation I might go for "A" is if I sailed regularly in and out of very busy ports
, and this had to deal with commercial shipping
every sail. This would not be so much for the close to port ships, but dealing with them once you left the immediate area, with the ships "Spreading out" if that makes any sense.
Our experience with an AIS
class B transponder on the east coast
(USA) was very positive. The biggest issue you still face is that most commercial fishing
boats don't carry transponders, but they are also usually lit up like Christmas
If I had the space and $$$, I would go with the Vesper unit. We ended up with the Em-trak transponder, wich does NMEA
0183+2000 +++ USB at the same time.