I started my campaign with 450BP and standard 12 availability, and so far I've had no regrets in doing so. It has allowed my player to play 'more costly' concepts like Free Spirit or AI without taking to much a hit in playability.
I'd say find out not only what power level your players want to play at, but also what types of characters they are thinking of playing. Maybe they want to play somethings with high entry costs, like those I mentioned, or a Drake or whatever, and the larger BP will let them do just that.
I didn't see much point in raising availability, but then I have no cyber characters, or heavily equipment dependent characters in my campaign.
I'm not as much in the 'give them everything they want' as All4 is (sometimes GMs just can't, for game balance or even personal GM ability), but if your players want a higher level, find out why, and if it sounds viable to you, then go for it.
Starting with 500 BP is like starting a D&D campaign at 10th Lvl - you miss all the fun parts.
That got me a laugh; I've played D&D so often at lower levels that I won't even consider playing at less than 5th, and my preference would be 10th+. The 'good parts' of D&D for me aren't the 'gritty fantasy' of low levels but the 'heroic fantasy' and 'super heroism' of mid to high levels. My character builds rarely even come together before 7th to 9th level!
And I probably have mentioned before I DMed a group from 1st to 17th and enjoyed every part of the whole campaign, but really liked the higher levels.
Not saying its wrong to love low levels - many people play D&D expressly for the 'gritty fantasy' that low levels embraces. Its just not for everyone.