Depending on the market you’re in (location wasn’t specified) if you have the 1400 available to you now, then get that one since it already has the filter built-in from the start. If you’re in the North American market, and can’t wait for the 1400 to become available, the XS with the filter should do you just fine.
The only reason I’d suggest the 1400 over the XS with filter is just that it seems the added flexibility of the 1400 is valuable, in the event that you ever decided to change either bank to a 24v system.
The new or “marine” version of the XS 1250 (ORI121217050) has the filter added, but costs more for the time being. The existing XS 1250 (ORI121217040) costs less but could still create HF issues in marine or other sensitive installations. The new XS 1400 (ORI242417040) has the filter added from the beginning.
Thanks all for your input. I am based in The Netherlands and the XS 1400 is available here and indeed similar priced as the XS 50 Marine. I guess I will go for the 1400.