The Skywatcher star Discovery 150 is one to avoid in my opinion. My experience with one that my brother bought has caused me to warn potential buyers. The plastic primary mirror housing that has NO collimation screws to adjust the mirror is the claim about no collimation required is verging on the ridiculous IMO. My brother's was out of collimation straight out of the box. This didn't inspire any confidence in their claims. I was asked by my brother to set up the Go to and telescope as soon as it arrived at his home. I was really [removed word] off that it needed collimating out of the box especially with no screws to do so. There's three side screws holding the mirror housing and with an hour's tinkering i managed to collimate it. This is a ridiculous situation and is caused by Skywatcher savings on weight and costs on the design and manufacture. It's said that it's for beginners so as not to need them having to collimate ever. This will result in the quality of their images deteriorating over use. And moving the scope around. Heaven forbid that it's dropped or knocked over/bumped etc. And a beginner having to try and collimate using the side screws then they will probably throw the towel in regarding Astronomy as a pastime.