Anne
Universal Credit is replacing JSA.
It will be the only benefit available to you while you contest your ESA Decision.
Be aware if you claim UC, the you will remain under the UC umbrella even if your receive a revised ESA Decision.
I can't tell you whether you will be better off under UC or by claiming "old" style ESA, however, if you are receiving the Severe Disability Premium then this is not payable under UC and as your claim will be treated as a new one then you will not receive any Transitional protection.
If you want to understand the financial implications then either get face to face advice or at the least put your information into one of the online benefit calculators
www.gov.uk/benefits-calculators Gordon
