The northern part of Praga
That's Praga Północ.
That's Praga Południe.
The Praga district comprises Praga Pólnoc and Praga Połundie. Praga Pólnoc used to be really rough years ago but I lived there for six months and never came to any harm. There were one or two streets where you wouldn't venture at night but there was nothing in those streets to attract a casual visitor or tourist anyway. Both it and Praga Południe have been thoroughly gentrified in the last ten years and are nice places to spend time. There's great shopping and loads of places to eat, beautiful parks etc.
Saska Kępa is returning to its pre-war vibe of being an artsy, bohemian type of neighbourhood, though self consciously so nowadays whereas before the war it was an affordable outlying district for artists to live. There were a number of very innovative modernist buildings constructed there at the time which have survived. It was supposed to be levelled by the Commies to create an industrial area but escaped that fate, thankfully. It would set you back quite a few million to buy one of those villas now. Park Skaryszewski is the local park and it's really beautiful. There are also działki full of flowers and veggies, very pretty.
The two parts of Praga comprise numerous different districts each with slightly different vibe, but they're all ordinary, middle of the road places, nothing especially seedy about them and if you take a look at property prices, you'll see that you can pay as much for an apartment in Praga as you would in any of the neighbourhoods on the other side of the river.
a pleasant leafy neighborhood with buildings of 3-5 stories
There are actually quite a few tower blocks as well but they're nicely landscaped and some of them have a lovely view of the water.