When I was comparing Allegiant to SW I found that car rentals were cheaper at MCO than at Sanford but you also have free parking at Pease which is a consideration. I paid $130 r/t for our SW tickets for our May trip and I just got a $60 credit this morning thanks to a DING fare. It's really a toss-up between the two IMO - you could probably get a cheaper fare with SW if you hold out longer but than you're taking the risk of not being able to get the flights you need because they're full (I got the last NS flights available on a Saturday and I booked almost 4 months in advance). We flew Allegiant in October and would have flown them again but we needed a Saturday flight which they don't offer. FYI - When I was checking fares earlier this month Allegiant was $130 r/t but I just checked their website again and the fares for the week we're flying have increased quite a bit so if you're going to fly Allegiant you may not want to wait too much longer in case they bump the fares up for your timeframe.