In reply to Anhub:
What shoes do you wear off-road?
Hokas take some getting used to. I love the Challenger ATR and Torrent off-road but just can't get on with the Clifton on road. I mix Brooks Adrenaline (firm ride but stable) with Brooks Ghost (so comfy but they're getting old, will probably get a new pair) and some cheaper/lighter ASICS Dynablast for speedwork.
Rotating different shoes can be good to prevent injury, but does have an initial high cost. If you only buy one pair, and you do enough training, you will likely wear them out before the marathon anyway 🙂
To be honest, trying a few out in a shop is pretty good and I've had the most joy from just picking the most comfortable fit (invariably the most expensive!). Most of the top brands are good in their own way, so choosing the best fit may work best to start with.
In terms of pronation or other stability issues, road running is less forgiving than off-road so having your gait analysed might be useful if you don't already know by looking at how your current shoes wear on the sole.