Hi Bob, you have a rather pleasant voice to listen to and your pronunciation is often great. Sometimes you choke up on a sentence or word, but that is natural considering that English is not your native language. You can improve the quality of your tutorials with better editing. Tutorials need to provide valuable information as quickly as possible. It is incredible hard to keep a large crowd entertained for 15 minutes if your message could have been conveyed in a much shorter video. Fundamentally, this is because you appear to have an idea of what topics you wish to discuss in a particular video, and then just start talking (ranting). Relying on conversational language during a let's play with friends is expected, but not during a tutorial that can be scripted and edited. Let me give you an example (03:10 in the video posted above), "... so ... so ... so ....". Dragging on your sentence like that is really confusing and contributes nothing of value to the video. In the same tutorial you say a lot of redundant things that obscure the core message for someone who wants to learn something from the video.
In conclusion: script your tutorials and know exactly what you wish to say. As a result, your tutorial will become shorter while packing an identical amount of information. Short is good. This will make your videos more persuasive to see. It should speak for itself that you should re-record chokes for a simple quality boost. All this aside, I think you are doing a great job.