I ordered the Baby Merlin magic sleepsuit when I was forced to transition LO to his crib when he started refusing to sleep in his swing suddenly. (He's almost at the weight limit for the bassinet of the PNP so I figured I might as well go for the crib.) He didn't like being swaddled, plus he was starting to roll over anyway so I put him in the only other thing I had, a sleep sack. He wiggled and startled all night long the first night so I ordered the magic sleepsuit. He slept in the sleep sack for the next few nights until the sleepsuit came and it was awful. He used to STTN in his swing and now he was waking up once or twice in the MOTN. Plus I'm sleeping in his nursery with him and all his stirring made it hard for me to sleep.
Baby Merlin came and he slept 6 hours the first night. We tried it for three nights in a row and we got around six or seven hours a night. Just as a test I tried the sleep sack again for two nights and both nights he only slept around 5 hours and one of those nights he almost woke up and I ended up holding his pacifier in place at 3 AM until he fell back asleep. We tried the magic sleepsuit again and we got 7 hours the first night back in it and we got 9 hours last night! That's the longest he's ever slept, even longer than he would sleep in the swing before. And I sleep better too because he doesn't stir nearly as much. The only negative is he can't wear all his adorable sleepers since he would be too hot in the sleepsuit but I'd rather get sleep! Just wanted to let y'all know how good it worked for us.
Re: I bow down to thee, oh magical Baby Merlin
Yes I just put him in a onesie under it. I haven't actually tried putting him in a sleeper with it, but since he doesn't seem cold with just the onesie I assume the sleeper would be too much. I nurse him to sleep so I do his last feeding in the suit. At first during the feedings I would keep feeling his chest and back of his neck to see if he felt warm but he always feels fine. On the other hand my arms gets sweaty from holding him while I nurse him in it. (He does a long feed before bed). The inside has a lining that somehow seems to keep him cool.
Fingers crossed, since we have a sweaty baby too.