Done a search, but as usual opinion seems divided, and I know zero about bottom brackets.

Getting a new frame with BB30. They also give an adapter for the reg BB. So, should I get the Force GXP or the BB30 crank?

Is the actual crank different for BB30 bottom brackets? I don't see that as an option when you order a groupset, or am I missing something?

Edit: the more I read, the more I dread the creak that BB30 can supposedly develop. So if I get the adapter and a GXP crank, can I totally avoid the disadvantages of the BB30? I read somewhere that even with the adapter you need the BB30 bearings? That didn't sound right at all.

If the brand of equipment your wanting to use offers a BB30 crank, I would go with that. If you already have a non BB30 crank use the adaptor

Yep, there is the answer.

In general there is a significant weight savings (100g?) without loss of stiffness when using the BB30 crank because it has an oversize aluminum spindle instead of a smaller diameter steel one. If you have the BB30 bottom bracket, you might as well take advantage of the weight savings. FSA offers BB30 cranks and is very well respected. The SL-K Light model is very good value for the price and comparable in weight to SRAM Red. The K-Force Light is the premium model. Very, very light especially in BB30.

I have a Force BB30, no complaints - for the price you can find them for, I think that they're tough to be in the BB30 world (there's a reason that there are tons of FSA Gossamer take-offs on ebay). Took me two tries on the install to avoid the creak, which was annoying but not a deal-breaker.

Buying a new Force groupset, so I guess I should go BB30? Don't think that loctite is even available in India, so I better order online.

OP,
This is pure philosophy call. A good question and you will get a divided response from knowledgable bike builders.
I will tell you if you use a Praxis conversion BB and a external bearing crank like Ultegra or DA, your BB will be utterly reliable.
BB30 is good...but only if the set up properly. This escapes some but not all bike mechanics. BB30 is just more sensitive to set up but many love BB30.

^^^^Indian bike shops don't even have tools for BB30 [I think - have to check]. I think I might be better off with threaded.

BB30 doesn't take extraordinary tools to install. A local hardware store is all you need. You can make your own bearing press.
What BB30 takes is basic knowledge...proper seating of bearings with loctite...and proper lateral crank preload with proper spacing that
keeps some preload on the inner race of the bearings and keeps the bearings seated. This takes basic skills which again escapes some but not all.
If you go external bearing crank, you can do it on the cheap and maintain BB30 bearings with Wheel Mfg spacers. A Praxis BB would be likely your most reliable route if going with an external bearing style crank.

You can get all the tools needed to service BB30 for under 40 dollars on eBay.

Bearing Press.
Bearing Tap.

These are what I use. They work flawlessly. Use Loctite 609.

And the replacement bearings are ridiculously cheap

This
If you can get the BB30 b/c it's lighter. Also as others have said make sure you read up on how to install, so you don't get the BB30 squeak.