My 5c into it; I'm a self funded Gold Velocity member (celebrating my third year of Gold membership in June just gone), travelling on average a return somewhere every fortnight or so, lets just say 50 sectors a year. Typically Sydney-Melbourne-Sydney; staying with my family in regional Victoria, catching the train to and from their place. Other times to the Gold Coast, Brisbane or Adelaide.
I generally book the last flight out of Melbourne back to Sydney (VA897 at 2100); and I aim to get to Southern Cross station by 1900 at the latest to get to the airport in theory by 1945, once transitioning from the platform to the Skybus. Some times, much earlier, where fly ahead is awesome.
On a typical weekend, all things going well, I'm usually in the lounge by 1930 and eligible to fly ahead on a 2000, 2015 or 2030 flight; I've even taken the 2045 flight at times. Yes, its only a 15 minute fly ahead, but any flight that gets me back home earlier is a good flight!
As a self funded flyer, I generally always book the cheapest option, and was annoyed last? year/2014? when they added complimentary baggage to all Y fares, essentially reducing the Gold benefit (and costing an average of $10 or so per flight extra). I travel lightly with a backpack, so this was a pain.
But to take away seat selection and fly ahead, well. Depending on the difference between the cheapest and the next fare bracket, I may be better off just dropping down to Silver and paying for lounge membership. Fly ahead is definitely my favourite and most used benefit, but if its going to cost me excessively to keep it, and even then, be subject to a potential change fee (it's been stated fees may apply), it's just not worth it for me. Seat selection comes a close second, and yes, whilst I don't usually benefit from the platinum row 3, I usually sit somewhere in rows 4-7 when checking in at T-48.
I don't need a flexible flight, my plans are generally locked in (and over 300 sectors, haven't missed a flight yet), and use fly ahead as my 'flex' tool.
As others have said here, there really isn't all that much difference between the VA and JQ product any more, yet JQ is generally much cheaper. Add in price beating Tiger fares, I've scored quite a number of $50 or so JQ flights, with no CC fee (that's part of their price beat promo). I may need to start re-considering my loyalties.
I shall await September 7 and re-assess.