Hi!
If you're happy with audio quality of your BDA-1, there is really very little reason to upgrade to a BDA-2 or BDA-3.
I can only accept the "dated" attribute if we are talking about compatibility as BDA-1 will not accept anything higher than 48 kHz through it's USB input. But if we are talking about audio quality, then it is as good of a DAC as anything I have heard. You can always use a USB-to-S/PDIF converter if you so desire and get higher sampling rates from your computer.
I own a BDA-2 but BDA-1 is just as good.
Quite frankly, anything above 24 bit / 96 kHz is ridiculous and there can be no obvious gain since analogue components like amplifiers are far surpassed by their digital counterparts when it comes to signal-to-noise ratio. There are many, many studies and articles including the ones published in respectable audio journals where it is stated multiple times there can be no audible benefit to recordings with sampling rates higher than 96 kHz.
Hope this helps.
Cheers!
Antun