Be careful in comparing apples to oranges here. One issue is of course what is the base rate, as mentioned. The other is the type of loan:
A HELOC will generally have interest only payments and can be repaid at any time, but is a demand loan, which means the bank can unilaterally change the conditions, like they did when they raised rates from P to P+1 a while back.
A closed term VRM will generally have interest and principal payments and be restrictive how much extra principal you can repay, but the bank (and you) needs to stick to the terms of the loan for the duration. Due to there being less flexibility for you, the rate on this will be lower. The repayment privilege conditions may vary between institutions and may be worth more to you than a few tenths difference in rate.
An open term VRM is like a closed term, but you have complete flexibility to pay back how much you want whenever. In return, you'll generally have a slightly worse rate.