Firstly, this isn't like American Diggers or other TV-archaeology shows. Far less drama and suspense, their investigations and results are more casual and less intensive (essentially, more realistic for amateurs) than similar shows. The detailed history and trivia during their search keeps it interesting, though it would be nice to have more detail or visual reference to where specifically the guys are searching on a site, IMO they use some strategies and techniques that would help fill in the progression of an episode, were they explained in the narration.
They don't find big-ticket items every time (rather rarely, like real life), but it remains solidly entertaining and intriguing if you've got an interest in history or archaeology/metal detecting, there's a little added drama (they freak out and tackle each other an awful lot, though) but comparatively little. The locations, history and significance of what they do and what they find is well-presented and has a solid depth of knowledge, and interviews with local experts in each show add a nice degree of depth/individuality to each location that's not commonly seen.
That said, my only real issue is with the hosts, or more specifically the script (or sparseness thereof). I like watching the duo find interesting and/or valuable stuff, the guys are interesting, if slightly quirky characters with a good dynamic and enthusiastic about what's usually a slow process, but hearing "juice", "nectar" "roundness" "roundness/nectar in the hole, baby" (+definition blurb) and randomly slanged terms repeated haphazardly and almost ad nauseum every time they find or extract a cool item gets a little old.
Your experience may vary if you're familiar with and/or enjoy the pseudo-terminology they use, but as someone who's not into the metal detecting hobby or scene (at least not yet, it does make me curious) the odd and very random terms get a little bit pointless and a little grating eventually, though not enough to kill the entertainment value of the show, and not enough to stop me from watching it quite yet. It's pretty good TV if you don't mind a random dash of silliness thrown in.