After reading various reviews of this Blu-ray, I was worried the picture quality would be awful. In a nutshell, it's not. The daylight, outdoor scenes are sharp, colourful and well-defined. Most of the mountain, forest scenes are pretty good with lots of detail. Some of the indoor, nighttime scenes have got a mixture of grain and (apparent) digital noise. There are some dodgy shots here and there with a lot of grain, but my suspicion is that these are pick-ups (perhaps shot using different film stock?). I've read online a comparison of the UK, US and other BD releases of First Blood. Apparently the UK release has the least DNR and is closest to the master source material (which may or may not be the best available master, but it's the one that's apparently been used for all the various BD editions around the world).
To my taste, the First Blood Blu-ray stands up fairly well alongside other catalogue releases (although it's no Bond-remaster). It's clearly better than a DVD. There are no compression artifacts. The colours and definition are better. The audio is solid too, with a Master Audio track available.
There's only one extra on the BD. This is a real shame. It's an interview with Sly. Sadly it's not even specifically about First Blood. Sly talks about the Rambo series as a whole. It seems it's taken from later Rambo (IV) promo material. (Strangely, this particular interview also appears on the Rambo 2 BD too... Odd that a rather pithy extra should be put on multiple releases!)
The film is great - in my opinion a joint best in the Rambo series, along with the latest (Rambo IV).
For a score, I think 4 stars is fair. The picture quality is OK, but could be a bit better and more consistent - as opposed to being so variable from scene to scene. It would also be nice to have (a lot) more extras.