The performance should be similar. I've heard that the 9555 draws slightly more power
, but even if true it should be so little that it makes no difference (I've got the 9505A, and it takes about 0.1A @ 12V when charging).
The 9555 is able to send and receive SMDS messages, and while these aren't going to be used for weather this might be a feature you want. The older 9505A only receives SMDS. There are newer versions of the 9505A that can also send SMDS, but I don't know where the cutoff is.
The 9505A has a very clumsy arrangement of stacking connectors for charging
data interface. You will need an RS232
adaptor to connect the phone
to your computer. The 9555 has a USB port which makes data interface much easier. (Is this used for charging
too? I don't know.)
The 9505A also has a clumsy external antenna
connection. The 9555 looks cleaner, but I have not actually tried it.
Originally the 9555 had problems with XGate drivers, but it is supposed to work
For what it's worth, I use XGate with my 9505A and an external antenna
. It works very well.