Perhaps I'm too ambitious or not ambitious enough - don't know. I acquired a GPS unit last year, and I do really like it a lot, for both astro, and just having the images tagged and using the map in LR. It is a nice feature. My problem is, I like to include an element of landscape - usually something large (mountain, lake/rock, etc.). I have tried both approaches, with and with out astrotracking, and have given considerable thought about it while the Milky Way was in hibernation over the winter. Worked on my post processing to some degree (which still sucks).
So, I'v decided to take both approaches rather than choose only one. Last week, I punted and ordered a Sigma 18-35/1.8 - it should arrive tomorrow. I want to shoot both approaches, and do some pano/stitching to boot. I also want to include some star tracking both wide field, and now that I found out you can go up to 300 seconds with a 200mm - deep sky. I have some other ideas now as well.
As to the body - I went with the K5IIs last Black Friday, due to the lower noise at ISO 1600/3200 (80% sure). Maybe the greater resolution of the K3 would have been better - I don't know (20% doubt). But, I made my choice, and just thinking that I will continue with it. I made my bed - and I am actually pretty pleased so far. If the new K3II comes out with killer low noise (greater IQ) at moderate to high ISO, but its really got to be great, I might reconsider. I doubt that it will (90% sure), but right now - I feel I am good till at least the K3II replacement (plus a year, for the price to come down). I do feel confident that I can and should be able to capture everything I want to do with my current body.
Now, its just practice, technique, skill, imagination, and most important of all - stop making small stupid mistakes. It's doing 99 things right and screwing one small inconsequential thing up - that always comes back to haunt me. The more I shoot the better I get, until I stop and then I regress - pretty quickly.
Getting back to the GPS for the moment. 300 seconds of tracking - even 200 seconds to ensure that the corners don't start to streak, is a lot of time. Everyone else need to use a tracker (lots more equipment) with polar alignment. The GPS with astrotracking is really wonderful. You really need to understand its limitations and to use its capabilities in the right way. That is the largest thing that I discovered last year. When and how to use it and to start considering how to combine it effectively with other techniques, based on what you are attempting to capture.
A long response to a short survey question......