I forget to wrote that you should also take your recent US Bank statements to show the funds, better take 3 last months bank statements.
SEE BELOW:
I've heard that entry into the US are refused sometimes while returning from Canada. Is it true?
Yes it is refused for those H1B visa holders those who do not have Valid H1B Stamp on the passport and try to get stamping in Canada through US consulate in Canada IF they are rejected and can not get Visa Stamp then they can not enter US from Canada and they have to then get the US visa from home country
Is there any basis to reject entry into the US. I've all valid documents but still is it under the sole discretion of the immigration officer to let me inside US from canada?
**But the INS officer is going by law and he/she is not against you, you have Valid H1B stamp in your passport and Valid I-94 and you are working in US, if they ask show them 2-3 recent paystubs, but I do not see any reason not to allow you in US,, when you come back just show your VISA page of passport, INS officer will ask you:
For what you went to Canada and how many days you were in Canada( tell the truth here and it has nothing to do with canada immigration)
what are you doing in US
have you baught anything from Canada
do not worry, just post your Landing Exp when you land or come back to US, it will help others.
Good Luck!!
Inder