Since there aren't really any "cheap" tickets anyhow, I'd say why not risk it as long as you are assured of a refund, either from your credit card company or buy purchasing some form of travel insurance. In either case be sure that you are really covered.

Credit card companies generally do cover you even though they aren't required to (because the ticket is purchased more than 60 days before you're seeking the refund) , but you may not want to count on their goodwill for $10,000 worth of refund money.

Travel insurance probably exists that will cover you, but just be sure you've understood the policy terms.

If MaxJet goes under, then you get your money back and buy tickets on another carrier that probably won't cost much more then than they do now. Keep your ear to the pavement about 3-4 months from now, in case you hear sounds of trouble from MaxJet, but I'd be willing to bet they will survive through the summer at least, if not much longer. I would gladly have bought my tickets on MaxJet if only they were flying to BOS. But I will not pay for business class over coach if it means giving up a nonstop flight.

One further thought: make sure you have the money to buy the other set of tickets BEFORE you get reimbursed, in case MaxJet folds at the most inopportune time and you don't have the reimbursement before your vacation begins.