The Good: Interesting themes as metaphors for Vampirism (sexuality, addiction, ancestry, teen angst), decent performances from Kelly McDonald and Damian Lewis, original British town-setting of Whitby, gorgeous cinematography.
The Bad: Falsely adveritised as a comedy-horror/thriller. "The Radleys" is none of those things, not scary or dark enough to be a horror, not funny enough to be a comedy, or thrilling enough to be a thriller. If you want a comedy-horror/thriller, check out any of the greats from the 80's ("Fright NIght", "An American Werewolf in London", "The Lost Boys" etc.)
No suspense or stakes (pun intended). No particularly engaging characters, they're all just a bit meh (even Uncle Will). Shaun Parkes is criminally underused as a practical mute throughout the whole film, despite maybe 5 lines of dialogue. Very poorly paced.
The Verdict: At best, "The Radleys" can only be described as a familial-drama with specks of horror (it doesn't romanticise the horror enough or show you the seductive sleazy appeal of the other side to be classified as suburban-gothic like, say, "American Beauty"). Despite the interesting above-mentioned themes and parallels raised in a grounded setting, none are properly developed nor explored ("Bones & All" does it waaaaaaaaaay better) and for all the talk of bloodlust being the most pleasurable thing in the world, you never see anyone having any fun with it. The best part is probably the third and final act (last 15 minutes), but it's a snooze-fest to get there and makes you wish it was something more... satiating than a TV movie. Even more so as a brit-flick that dares not belong to the gamut of historical epics, rom-coms, or biopics.