I would agree.
While there is a possibility of getting more for that name, I would be a seller at that price and then reinvest. It may be worth your time to counter offer with a modest increase in price if you really need to get more out of the name.
I think it sounds like a fair offer .. not a particulary lowball one .. I would take the offer at that price and reinvest as suggested.
I have tradeshares dot mobi and have only had 1 $70 offer for that.. so I think your name has done well and that is more than a fair price at the moment, bearing in mind other extensions are available and its low search results for the term.
If you feel it is so low ball it must have fallen well below your expectations for this name.. so you either hang in there and hold or try a modest increment as a counter offer and let it go..
I think this is an extremely good offer for the name, inno way is it a low ball offer, i'd take the offer and run, i think countering his already good offer could ruin your chances of getting rid of it. You will then have a good bit of cash to get a nice LLL.mobi IMHO