OK, let's get to the nuts and bolts of it. There is no such thing as ONE "best" combo amp.
My personal favorite is the Mesa Walkabout Scout combo, but I like a fat, round, "vintage" tone. Many who prefer a modern, clear, neutral tone would HATE the Mesa Walkabout and probably prefer something like the Markbass.
You are asking a question for which there is no answer.
Now, if you narrow down the parameters, we can help. What we need.
1) BUDGET - What is the MOST you are willing to spend. Period.
2) WEIGHT - And ACTUAL number of the most weight you are willing to lug....not just "potable". Portable to me is a 15" Mesa Walkabout Scout combo in one hand (52 pounds) and the extension cab in the other (45 pounds). Others would find that extremely heavy.
3) TONE goals - Do you like clear and bright or warm and wooly?
Until you give some details you will keep getting opinions that are all over the place and don't answer you question.....for which there is no one answer to begin with.
There. Is. No. "Best". Combo. For. Every. Bass. Player. Period.