IMO (of
course...) go with the simple one the meets Paul's interests. Unless they're the same price, then choice is a (little) harder, but I bet the simple one is cheaper (busy at moment, haven't checked).
You have a full life, lots other stuff to do, lots of _that_ pretty important by itself. Logistics will be
enough challenge w/out adding deep tech detail. You'll pay a little more in time recording results "manually" compared with ideal setup of the Davis system; but doesn't sound like tech spins your wheels. <g> And the big system could be a BIG issue setting up and maybe risk failure to get there. So KISS.
Advice: On receipt immediate test for proper function, including connection with phone and returning more or less plausible temps from various places. Any function you think you paid for and will want, test it. Immediately. Keep the package for a few days, see if things still work after being powered up a while. Good? Good. But the failure rate of cheap electronics (ie, almost all electronics available today) is significant. Waiting to test can cost you both time (winter's coming) and money (return window).
If all goes swimmingly, somebody can approach a more expensive purchase later, knowing what worked, what more was needed, etc.
Cheers,
Rufus