Tell me about mirrorless DSLR cameras

Tell me about mirrorless cameras? Are they worth the price and what is a decent affordable system.

I currently have a Nikon D300 dslr with several lenses and it is OK but it doesn't seem to do as nice of shots as I would like or it is a lot of work to setup nice shots. It is also several years old now and my phone is a higher pixel camera than it is. My wife and I are in our mid 50's and have more traveling to do and are looking forward to traveling in retirement. We would like a really nice higher end camera that is easy to use but can also do serious setups if needed. I would like to capture the milky way at night here in AZ etc. We are mainly into outdoor photography.

I suppose it would make sense to stick with the same brand if the lenses will interchange.

Edit: I am looking hard at the Nikon Z5 for features and price point.

Thanks

 

Steve:
Nikons and Tundras work really well together! Mine certainly do and I have more Nikons (6) than Tundras (2).
The D300 was a fabulous body but is extremely dated at this point (about 15 year old technology). There have been massive improvements with sensors since then and cameras are computers and software. Mirrorless have improved on autofocus and focus point capability. If you are looking for a camera body to use for 20 years then that is not realistic. If you want to shoot the Milky Way then you should select a full frame body (Z5 works) and a fast (low f stop) wide angle lens. If you are only toying with Milky Way at this point then you may want to get the old but fabulous 14-24 f/2.8 used (I see them being sold for $600-800) and use it with the FTZ II. The more you get into photography the more expensive it becomes - especially if both spouses are involved (like for me). You may want to take a few classes to determine if you want to take the deep dive.
Steve

 

I already have several lenses for my D300 so that is why I am looking at the Z5 with the FTZII adapter. It would ge me started until I could get newer / better lenses.