Depends what you're after. It's nothing like Glasto and to be honest there's always a few secret sales in May for Glasto. If you set up an alert on the see tickets page to let you know when it changes.
As for T, I had many a good year at Balado but was getting tired of the repetitive line ups and pop orientated way the festival was going,so I didn't bother going last year and wouldn't go to the new site unless there was a line up that suited me. Calvin Harris every year just doesn't doit for me.
The problems with the new venue have been well highlighted and to be fair to Geoff, he appears to have listened and they're heavily promoting the changes to the site this year which will hopefully make it a bit better. Traffic attending last year turned the surrounding area into a chaos zone and organisers basically did zero to help. The roads, or lack of, around the site haven't changed so there's a chance the same problems will happen again.
If you like the line up and come prepared fortraffic chaos it's worth a punt. You'd probably need to camp as there's hardly any off site options nearby. The campsite itself is sometimes like a war zone without the sunshine.
It won't sell out, so if it was me, I'd wait and see if I could get a Glasto ticket and if not, you could always get a ticket for less than face value nearer the time.
Alternatively go to a festival abroad. They're far cheaper, weather is generally better and it's more like a holiday.