My DD is 6 months old and I have used almost every swaddle on the market in desperation to help her sleep. I wasted a lot of money here's what I think of the ones I tried.
Halo sleepsack - this is a sleep bag with Velcro wraparound to secure arms down. Do it up tight and it's pretty secure my DD is an escape artist and found it hard to get out of. Good for winter quite warm with appropriate clothes underneath and we always tuck in with a sheet and blanket at about waist/chest height to help feel more secure.
Baby studio Velcro swaddle. This is like a pouch style with arms down and wrapped secured with Velcro. This was ok at first but developed some stretch and the Velcro wasn't as strong and she could bust it open.
Ergo swaddler. Not a fan. These are where the arms are crossed on the chest and Velcro'd around. The Velcro didn't stay sticky long at all so she was able to wiggle around and get a lot of movement. Bub was tiny (2.65kg at birth) and the small didn't even last her very long.
Ergo cocoon zip up swaddle with press stud arms so can have arms in or out. No good for our newborn. Using now as a sleeping bag with arms out though. As a newborn this style allows them to get their elbows up around their faces and the fabric bunches up under the neck too which I didn't like. Currently using the 2-12 month 0.3 tog with arms out as her sleeping bag and it's lovely soft jersey. Can get different tog weights which is good.
Love to dream arms up swaddle. Lots of people swear by them. Didn't work for our DD. Having her hands up like that was a major distraction and she just.would.not.sleep in these. This is a zip up swaddle in very thin fabric but may be able to get thicker TOG for winter not sure.
Love to dream 50/50 arms up swaddle. This is the same idea as the other love to dream but has zip off arms so you can transition to arms out one at a time and then use as a sleeping bag. Not a huge fan of this as a sleeping bag as the arm holes are quite large once zipped off.
Muslin squares or stretchy wraps for wrapping. My Houdini would be out of these so fast it was sooooo annoying as she would wiggle around and get her hand free and wake up from touching her face.
So what actually worked for us? Lol. When she was 3 months old I discovered this AMAZING swaddling technique and it was escape proof and she loved it.
My DD sleeps best arms down by her side wrapped tight. We've just transitioned to arms out now she's over 6 months and rolling. Goodbye sleep! With this wrapping technique I used a cotton flannelette wrap as its not stretchy and stays firm in place. For the part to wrap their arms down I used a soft cotton wrap (again not very stretchy) folded into a strip about 15cm wide.
Most babies have their arms up as this is their natural position but this doesn't mean they like it or that it won't bug the crap out of them so much that they won't sleep so just because they put their arms up doesn't mean they don't need/want wrapping.
Ok having said all of this. All babies are different. What worked for me/didn't work may be different for you. My best advice would be don't spend too much money just yet wait til bub is here see what they like how they sleep best. Who knows you may be blessed with the ultimate bub who sleeps anywhere, anytime in anything. I think one might exist somewhere 😜
You don't have to wrap. If bub likes being free and sleeps well go with it as they can become very dependent on being wrapped (we found this out the hard way as first time parents). Advantage of a sleeping bag is they can't kick covers off and get cold then wake up calling for you. My DD kicks constantly in the night now so without a sleeping bag she would always have her legs out. Also for sids its safest not having anything, or minimal bedding in cot so with sleeping bags you can add/remove clothes underneath rather than thick bedding layers. Just make sure the sleeping bag fits well around the neck you want it quite tight do bub can't get their head down in it or it rise up over their face.
Great discovery I've had recently are bonds wonderbodies long sleeve bodysuits. The lightest softest stretchiest cotton thin bodysuit I've found - perfect for sleeping and an easy thin layer under clothes for winter. I'm just using a 0.3 tog sleeping bag at night (hot in Adelaide!) with long sleeve bodysuit to keep her arms from getting cold during the night, no pants. This is the perfect combo for us at the moment. As it gets colder I'll go to 1.0 tog (I have a lovely Plum bamboo jersey one ready to go) then in winter 2.5 tog sleeping bag with a onesie +/- short or long sleeve bodysuit depending how cold it is. We heated her room to 17degrees during winter. In summer I try to keep it 25 or under.
Sorry for the essay hope this helps!