Hi Flying Texan, I am ordering a Trial Master for a couple reasons. First, I like the option of the second battery. If you order the Field Master you cannot get the second battery as it comes with a premium sound system that adds a subwoofer under the rear seat where the second battery would go. From all my research, if you want to end up with both eventually, best to spec the second battery and then have an audio car shop upgrade any speakers, amps and add a subwoofer to the rear boot area or in a secured subwoofer enclosure. If you order the Field Master, your only rim choice are the 18" alloys, which I don't like the look of. If you order the Trial Master you can pick any rim tire combo they offer.
I have found that it is better to spec a Trail Master and option up from there then starting off with the base Station Wagon as you actually save a little money and end up with the RAI, Raised Air Intake for Free, which you can then easily take off and purchase a new trim plate from Grenadier or so we have been told. You also may get the Belstaff Trial Master Jacket for free, although not 100% sure it is still part of the North American spec and I think you also end up with the compass/altimeter too.
In regards to the newer 2020 Defender, I own one and it is an incredible vehicle and IMO is the number one 50/50 on-road off-road vehicle in the world with it's 4-wheel drive system and on road manners. A pure joy to drive and fast too, zero to 60 in just 5.8 seconds with their straight 6 P400 petrol engine. I cannot say enough good things about this vehicle. I give it 100%. Only reason I am selling is to go onto another adventure by purchasing the Grenadier, which I believe will be the number one 65/35% off-road / on-road vehicle in the world. IMO you cannot go wrong with either one. I have owned my 2020 Defender since new now for 2 1/2 years, still in love with it. I test drove the Grenadier and came away even more impressed than I thought I would be and Love it Too. Jump on in, the water is fine. There is no wrong decision here. We are all fortunate that these 2 vehicles exist for our endless pleasure and joy. DaBull