Before watching this series, you almost need to dismiss the original, or at least see this series as a continuation, rather than a retelling, or see it as a 'reimagining', but I hate that buzzword, so myself I'd rather see it as a continuation; liken it, if you will, to the Will Smith 'I, Robot' film - not an adaptation of the book, more an addition to the universe it immerses itself in.
That said, the series isn't that bad; Ian McKellen makes a great Number 2, carrying just enough menace and authority without looking ridiculous. And Jim Caviezel makes an okay Number 6, having enough guile and determination to challenge authority, but being just flawed enough to not have it all his own way, but lacks the on-screen presence and gravitas that Patrick McGoohan (R.I.P.) carried off so well in 1967/8. The series does keep you wondering what's going on, but you sometimes wonder - particularly by episode 5 & 6 - if those involved in the series' production even know, as it does seem to amble about a bit toward the end and its whole point seems to get lost along the way. The main problem with the show is that it takes itself far too seriously; maybe it was felt that you couldn't make it too humorous, lest it makes itself look silly, but its sly wit is what made the absurdities of the original series easier to swallow and what made it and its characters so endearing, not to mention enduring. The lack of humour in the modern version makes it difficult to care about anyone very much, '147' being about the only one to bring even the slightest bit of levity to proceedings.
The show does pay some lip service to its predecessor; not least the setting of The Village (although Portmeirion it ain't, it lacks any of its charm and is very uniform in design, but perhaps that's the point), but the eagle-eyed amongst you will glance a penny-farthing in the nightclub, echoing the motif from the '60s and of course Rover is there, which still is a weather balloon with attitude, but seems to have much more presence on-screen, despite its short appearances and does look genuinely menacing. But one omission that is unforgivable is the lack of even the slightest mention at either beginning or end to Patrick McGoohan and George Markstein, co-creators of the original show without whom the remake wouldn't exist. Hopefully, the eventual big-screen adaptation will redress that issue.
In all, a good show which is watchable with some good performances all-round, but hard to actually enjoy, although the key elements and subject matter of the show - of information and surveillance, the value of the former and the apparent reckless use of the latter - is as relevant today as it was then, if not more so.