[Pblais]

There are no open standards. A variety of chart formats are proprietary. User friendly depends on the user.

I've been happy with Fugawi. It's about $200 supports Maptech BSB, Navonics, and ENC formats. Works well and you can upload routes to NMEA and Garmin and a few other Chart plotters. There is a free demo install. They increased the price to include a the proprietary Navonics chip reader, so the extra price is perhaps worth it. They also support a Pocket PC and Palm export format that you can use to upload to a small handheld device and that works pretty well.

No software exchanges maps with chart plotters except the proprietary products like Garmin. Fugawi does export to Palm and Pocket PC but nothing else.

As far as being stable there is NO ONE that can be considered stable, but there are a few that have been around. Being stable would be considered a bad thing since Raymarine would likely try to buy them out and bury the product. On the higher end Nobletec is a good one but a bit on the expensive side.