dogs - shiba inu

We've got a Jack Russell/Corgi cross who has done a valiant job of taking care of the house..tolerates no one within 50 metres....Only one attempted break-in in 14 years - and probably because he went ballistic...But since he's 14+ and getting his own health issues...in doggie terms sadly and likely not a lot longer to go...
Anyway, at a couple Royal Shows we've been impressed with the Shiba Inu's on display. We've always loved seeing them in Japan. Right size, pleasant enough at the shows....but are they any good as a watch dog? I've read they are not particularly obediant - nothing new for us....And not a good idea to let off the leash...ditto for our runner...
Just wondering if by chance anyone here has a Shiba and what they think of them....