re: USDM & AA account balances to convert from March 28th
So if it all becomes the same rates as AAdvantage what are the actual advantages? The rates look like going up across the board. Is the only benefit a stopover each sector (2 in a return trip) with open jaw as well? With the flexibility to mix and match cabins on Departure/Return legs?
AAdvantage does not allow en route stopovers.
Since AAdvantage allows one way awards (exactly half that of a round trip), making open jaws (single or double) is easy.
Generally speaking, AAdvantage routing rules are more restrictive than US Dividend Miles. Flying between two non-adjacent regions in AA can only be done via a given set of regions, which is not defined on AA's website (but has been documented on other FF websites). A major one of note is that flying between South West Pacific and Europe can only be achieved via some select Asian ports (Singapore, Bangkok, Tokyo, Hong Kong... possibly a couple more). You cannot route via the Middle East (well, you can, but you'll pay for two awards rather than one). So, for example, to fly Qantas between SYD and LHR, you would need to find availability on QF1 which spans the entire route as a continuous flight. If you fly QF SYD-DXB and then, say, DXB-LHR on BA, even if the two are within the correct connecting time, you will still pay for two awards (cf. on US DM this would be considered one award). EY is an AA partner, however due to the rules aforementioned, it is impossible to redeem only one award for any redemption which goes between the South West Pacific region and Europe (or another region for that matter) on EY.
Most prices in points will go up, only a few choice ones will go down. AA currently have a cap on the number of points annually that can be purchased.
Apart from that, some awards on some airlines can be booked directly using AA's website which skips booking fees and necessitating having to call up. Otherwise, if you're a US DM classic or book on some airlines that can't be booked using the website (CX comes to mind, of course), then you'll generally find AAgents are more switched on and not as geographically challenged compared to the US DM ones (which means usually better service, but that means you can't pull fast ones on them like it was on US DM).