Seems to be a bit of misinformation here about Logic Studio educational. If you buy this in the UK at the student price (£118.00), then you are in the same boat as everyone else when it comes to upgrading to the next release.
The confusion comes from Apple's pricing. For example, I bought Logic Studio 8 at the educational price of £118.00. When Logic 9 was released I wanted to upgrade. As normal, I could upgrade for the standard price of £159.00. The problem is that for me to buy Logic Studio 9 was still £118 as an educational discount. So it actually worked out cheaper for me to buy the full version of Logic 9 than the upgrade.
When Logic 10 comes out I will no longer be a student, so the only options for me will be to upgrade (for £159, based on current prices), or buy the full version for £399...not that I would do that!
I don't know about Pro Tools, although I have PT9, bought for just over a couple of hundred from KMR at educational discount. When I want to upgrade to version 10 or whatever I'm hoping there will be a discount, but if not I'll be able to upgrade for the same price as everyone else (according to my dealer). Also, no key features are missing. Anwering the OPs question, no - there are no drawbacks getting the education version (of PT or Logic...don't know about Cubase). Hope that helps