"1. More readily; Preferably.

In expressions of preference rather is commonly preceded by would or in formal style should: 

We would rather rent the house than buy it outright. 
I should rather my daughter attended a public school. 

# The use of had in these constructions may now be more infrequent than it once was but is still encountered in reputable writing: 

I had rather be dead than be a slave.

2. Used to mean 'fairly' or 'to some degree', often when you are expressing slight criticism, disappointment or surprise:

The instructions were rather complicated. 
She fell and hurt her leg rather badly. 
I didn't fail the exam; in fact I did rather well! 
It was a rather difficult question. 
It was rather a difficult question. 
He looks rather like his father. 
The patient has responded to the treatment rather better than expected. 
He was conscious that he was talking rather (= quite) too much. 

  
3. Used with a verb to make a statement sound less strong:

I rather suspect we're making a mistake. 
We were rather hoping you'd be able to do it by Friday.

4. Used to correct something you have said, or to give more accurate information:

She worked as a secretary, rather, a personal assistant. 
In the end he had to walk or rather run to the office.

5. Used to introduce an idea that is different or opposite to the idea that you have stated previously:

The walls were not white, but rather a sort of dirty grey.

6. You use rather than when you are contrasting two things or situations. Rather than introduces the thing or situation that is not true or that you do not want.

The problem was psychological rather than physiological.
When I'm going out in the evening I use the bike if I can, rather than the car.

7. On the contrary = instead.

He didn't call; rather, he wrote her a letter.

8. To some (great or small) extent.

It was rather cold.

9. To a degree (not used with a negative):

Rather tasty = Quite tasty."

# Rather vs. Had Better.

Had Better (Present or Future).