Think forward a year... do you REALLY want your ex dropping by your house all the time, having to leave your own home during the weekends, not being able to have company over, dad bringing new girlfriends into your house? Dad bringing friends and parents and his GF's kids over to your house? Aside from the invasion... think also of the mess, the cost of entertaining, the cost of having strangers over when the house is a mess (emotionally, unless you don't care about having to keep your house spotless all the time). There's also going to be (inevitably) some Disneyland Dad stuff going on. So things will be fun and special when dad is around... and you come back and spoil the party. Lovely. (As opposed to having special 'coming home rituals', you're the party pooper when they're tired and cranky from a fun day with dad).
With 2 homes when things are civil you can invite each other in... when it's ALL you can do to stay civil for 5 minutes you have a private space all your own to retreat to. There's only 2 logistics to arrange (drop off and pickup) not ALL the logistics of having people over to your home.
The majority of the 1000 reasons to have 2 homes are personal, YOUR mental health and well being and boundaries and pocketbook and time... (as well as his). Or you're just bringing the fight TO the kids. If the whole idea of divorce is not to have the kids constantly watching the two of you at your worst (angry, depressed, stoic, uncomfortable) and to move on with your lives... you need to make sure you're not just making it like staying in a dying marriage, but adding girlfriends and boyfriends.
But there's also kids' well being to consider (which of course you are, not saying otherwise, you're obviously wracked with trying to consider). Not only will you 2 be bringing a strained relationship ***to them*** each and every time you guys have to put on a happy face, but also the confusion of the kids on "But why does mommy have to leave if we're going to have a party?" The confusion as to why rules are completely and totally different in the same space (one reason why substitute teachers always throw kids for a loop is that rules change dramatically, even with the same curriculum). The confusion of the kids as to why they can't go with daddy where HE lives? Are they not welcome? Does he not want them? Are they not special enough, because he takes OTHER people to his house, why can't they? There's also the spin factor: Kids GENERALLY prefer to have 2 over 1. ((Heck, so do adults. Would you rather have 2 vacations, or 1? 2 presents or 1. 2 houses -like having a summer home/ cabin/ etc.- or 1?))
Neither way is easy, but one way is less hard.
There's a third way that's even MORE difficult in some ways, less in others, and that's THREE homes. 2 of which the kids aren't welcome at. A lot of my friends growing up griped that that was what THEY would have preferred, but the few who did were out and out miserable/ self centered (the world comes to them)/ and the parents were miserable (since they had nothing that "belonged" to them and them alone in the house they often felt like babysitters)/ had HUGE abandonment issues (because they weren't welcome at their parent's other houses). Some families I knew started off with 3 homes, but since they DID allow the kids at "their" houses, eventually it just became easier on everyone to have 2 homes.
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The thing is though... there is NO "One Right Way" for any family. If you're honestly considering the 1 home thing... TRY it for awhile. While my husband and I have been separated it's been *exhausting* to do essentially the same thing... and most of those I know have had the same experience... but just because that's what "usually" happens... doesn't mean it won't be the perfect fit for your family. It's a logistical nightmare with boundaries being crossed all the time, but that doesn't mean that it might not work.
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If you DO go with 2 homes... you might want to think about this less than ordinary schedule it's about 60/40
M-F w Parent 1
F-M w Parent 2
During the summer... switch.
M-F w Parent 2
F-M w Parent 1
Parent 2 picks up from school on Friday, and drops off on Monday. That way both parents stay active in the kid's educations (since they're both interacting with the teachers 2 & 3 days a week without having to throw a wrench in the works midweek, and homework that goes home, goes to school the next day, no 'but I forgot my backpack/ papers/ books/ at Mom's house)... have almost equal time... and the schedule is SET. The exact same thing happens EACH week... instead of "whose weekend is it?".