Resolve is great. Like any high end editing/grading software there's a bit of a learning curve, but the free version has everything you'd want and there are plenty of tutorials on YouTube. Couple of pointers:
1. Your PC hardware needs to be up to spec, graphics card especially, and more so on the last two versions (15 and 16). Version 14 was a bit less demanding and IIRC supported native import of HD-AVC.mp4 files. You can download all past versions on the Support page.
2. When it comes to export, the native (Main Concept) H264 encoder is pretty ancient, but it does also support NVIDIA hardware H264 encoding. An arguably better option is to export to a 'visually lossless' intermediate format (Cineform, DNxHD, Grass Valley) and use a third-party utility (Handbrake, VirtualDub2, FFMPEG) that supports x264 encoding. But you'd be working with very large intermediate files.
3. One thing I especially like about Resolve is that it doesn't clip the 'superwhites' (specular overshoots) on import, which leaves scope for recovery ('pulldown') of near-blown highlight detail with the grading tools that are available. Like many video cameras, the HF-G40 does have a tendency to over-expose a little when shooting in full auto exposure mode. Most other editing programs (Premiere Pro included) clip the superwhites on import.
As for Premiere Pro CS6, I have no experience there, but if it doesn't support native import of your G40 HD-AVC.mp4 files probably the best (and only) option would be transcoding the clips to an acceptable intermediate format; Cineform would be your best bet. For that I'd suggest VirtualDub2 which is free and uses the native Cineform SDK. Can't include a link.
Hope that helps.
Yesterday I start a video project with Premier, not using the presets, but with the HF G40 directly connected to the IMAC and it worked fine until I saved the project and when I got back to it twithout the camera connected, he video clips would not show. If I download the video clips to a folder on IMAC and start a project with presents or no presets the Premier would not show the video clips but an yeloow screen saying No Media Enconding.