If you want to get to paddington in a reliable way, the HEX is the only option. As I have posted ad nauseaum the Piccadilly line can be woefully unreliable and the wait at LHR (depending on station) can easily be 10mins. However, getting from Paddington to Victoria is not so predictable (I know as I do this at the end of every working day).

The Circle line runs every 8 minutes. It is much more reliable than years past, but when they do drop a train it is one hell of a gap and taking a Wimbledon train to Earls Court is a hassle.
A cab to Victoria would cost around GBP12 and take 10-15mins. But the queues at Paddington can be quite length in the morning.
Bakerloo to Oxford Circus and Victoria onwards is the least worse option. Get in the last car at Padd for a decent chance of a seat and a simple cross platfor interchange at Oxford Circus.

If you don't mind getting up evily early then the Piccadilly line is fine. If you want to cut things fine and don't mind spending the extra cash, the HEX and Bakerloo/Victoria.