I have recently been in contact with a developer that is making similar changes to make gigCalendar compatible with Google Calendar...which has some very exciting possibilities! I will post more hard data when I receive it but this developer has also provided a fix for exporta.php which hasn't really worked correctly since gigCal's initial release. Here is a quote from our recent correspondence:
the ICS file generated does not make Google Calendar happy, so I'm moving the whole thing into the main gigCalendar component and adding a format module similiar to the RSS feeds, so it can be specified a bit more exactly what should be in the iCal card, as well as stripping out or handling multi line content.
If I can get that to work, I probably won't bother using GigCalendar's calendar display functions on the front end, Google just has a better implementation there and no reason to re-invent the wheel. Instead GigCalendar will feed into Google Calendar, which can then feed back into GigCalendar for detailed display of data - and AttendEvents for RSVP functions.
Basically, I'll take it as far as I need it, which should add in a few extra functions, but not much past that.