Cuffs is a bit unusual for a police drama, it mixes a fairly light tone with some quite serious story lines. It's realistic and fast-paced but it generally isn't gritty. There's a lightness that reflects its summer-in-Brighton setting.
Once you watch several episodes back-to-back, you start to notice how the focus isn't on the crimes themselves but the people who deal with them. The characters' backgrounds and personal situations develop over the series, and by the end we can see changes in how they relate to each other. It's not a soap, but it has the same idea of presenting characters we can relate to in various ways and finding ourselves attached to them, and that's what keeps you wanting more. The episodes also make connections between the disparate characters and crimes in a way that you wouldn't expect, overlapping one theme with another. Some of these connections are a bit "blink and you'll miss it", but when you re-watch this comes across quite well.
The cast work very well together, it's a good and balanced ensemble. The interplay between Moffat and Hawkins for example really makes us feel they have been working together for ages, it feels very natural when they have to help each other with problems outside work as well. Prager and Moretti's police constables are another good "double act", thoroughly enjoying their job despite having very different personalities.
Paul Ready deserves a special mention for his portrayal of DI Kane, a very strange man indeed who is simultaneously harsh and vulnerable. His is perhaps the most intriguing character of all despite having relatively few scenes, because Ready seems to be able to give all of his lines a depth beyond what they are on paper, as if there is far more unspoken than spoken. At first he seems not to care, but the indifference turns out to be an obsession with doing his job as well as he can despite his difficulty with socialising. He makes us want to know what makes him tick, and hopefully there will be a second series where we find out more.