Rex driver! I drive comfort all the time with cabin heat at 20c.
On a quick scan through, I didn't see a mention of geography. Hills make a difference so if you live in an area like I do where everywhere is pretty much up and down hills (even the motorways have many long steady climbs and falls) then you need to factor in that variable too.
I have managed 118 miles before the Rex started in good weather at 16c driving around 56mph on mixed mainly flat roads. I ventured into the hills two weeks ago with temperatures around 5c and I was looking for a charger after about 95 miles.
As has been said, preconditioning makes a difference especially when it's cold so if you have to stop for any length of time without the benefit of a charger then that's a problem to add in too. The restart will be from cold losing you valuable range.
I had a similar conundrum when I bought. Both Bev and Rex would have done for my usual daily needs but I have a fairly regular 118 mile round trip into the hills. Whilst there is a charger the other end, I could not guarantee it. In the heat of summer the Bev may have got me there and back, in winter it was a no go so ended up going for the Rex.
I also think the Rex is a no brainer for the ability to do longer journeys just to add the flexibility of not having to stop and charge so often if it isn't convenient. So for instance, I have to go to London next week which is a 140 mile trip one way. I would have no option but to stop on route in a Bev adding 30 minutes to my journey. Although I probably won't take it, I have the option of not stopping in the Rex.
When I mention this to fossil drivers, they throw back at me the question, "well what if you had to do over 200 miles?" I just point out that you shouldn't really be driving for that long without a break anyway so stopping to charge ceases to be an issue, it's just a further necessity like food, caffeine and a toilet which you have to do some planning for anyway.
The decision to go for the Rex has meant my backup SUV has done 300 miles in 5 months of i3 ownership and most of that was down to snow and load carrying. The i3 has done 6,300 miles in the same period with 6,000 of those being electric. Of the 300 Rex miles, more than half was me deliberately emptying the tank (first time to test the system and second to refresh the fuel). Overall I reckon the true balance of EV/Fossil driving has therefore been 93% -7%. With the Bev, that equation would probably have been nearer 84% - 16%.
Was it worth the extra few thousand for the Rex, you decide? The additional fuel cost per year would probably only be around £200 but I bought an EV to minimise my fossil mileage anyway and somewhat perversely, the comfort blanket the Rex offers allows me to minimise that fossil usage.