Thats exact situation I was in, in June. Its sooo stressful. We only had a few days to book....Sunwing only gave us 5 days to decide. So we ended up doing it because it was pretty cheap, considering were booking a year in advance. However, since we've booked with sunwing, they keep going back on us and changing things they've said and telling us that we can't have things they said we could. We were told if anyone else wanted to book into our group they could, at the rate we paid...They can't, actually they can't even book into our hotel through sunwing....We were told that our early booking bonus was up until Dec 31, and after that they would be charging $30 per person to the total, with final payments being made 45 days prior to departure...Which was fine we were totally cool with that...On Monday one of my guests got an email from sunwing saying that the early booking bonus deadline was Oct 31, not Dec 31...So I got in contact with my TA and she got ahold of sunwing and they said they made a mistake by telling us it was Dec 31 and that was to bad..the deadline was Oct 31...She ended calling the supervisor of the group department and finally got them to settle on Dec 1.
This is only 2 problems we've had with them, I also had problems with their travel insurance and shortly after we booked sunwing called my TA and told her that they charged us the wrong price, only the first 14 people to be booked into our group were guarnteed the price we were quoted even though we all booked before the day they told us we had to and they told her that they were going to contact the others that booked later then the first 14 and charge them more!!!!!!! My TA almost went through the phone at them....Needless to say they didn't end up charging them more.
All in all if I had my time back I wouldn't book with them, but thats just me.
Good luck in whatever you decide to do