I wrote way too much sorry. TLDR - Zempire & Dometic are great tents but consider a cheap dome first to see if your family likes camping.
If money isn't an object then the new Zempire tents are as big as you want them to be (they are modular). They don't go up quite as fast as the instant-up Coleman's but they aren't that much slower either. I regularly camp side-by-side with an Instant Up (the kids are in it) and I'm in an Evo TS. The coleman can't handle as much wind and rain as the Zempire before collapsing or leaking but it is like half the price - and we are talking wind storms and some pretty heavy rain.
The awning out the front in the Evo is fantastic for going in and out of the tent in heavy rain though the zip-on awning door isn't quite as usable as I'd like (it's mesh or solid, not both).
The big thing you want to pay attention to with any tent is going to be much space it takes up when packed down - length but also height & width - i.e- will it fit in your car boot and allow you to take anything else like clothing, toys ,sleeping bags etc. Even my TS takes up quite a lot of room. The TL or Santorini would be pretty large.
Also weight - if it's 30+kg, can you even get that in and out of your car without ruining your back? To me, that's always been the killer for any canvas tent.
I guarantee if you get a large tent you will soon find yourself checking out for roof racks and a roof pod for your current car (or a trailer). You'll definitely need to if you plan on having another child.
Tents I have experience with that are relevant to your situation:
Coleman Instant Up 6P Gold Evo Tent - good and easy to put up but they are prone to damage if the tent fabric gets caught where it hinges and the metal parts aren't that strong. Our scout group has had 3 break in the last 12 months and none had been used more then 4 times. My tip- don't rush putting them up or taking them down. If going for a coleman consider the 'Lighted Northstar Darkroom' version instead. $100 more but it looks like a better awning design that would stop rain pouring in while you get in and out of the tent. We use this for 2 kids usually but it fits 3 stretchers comfortably with a little room to move around. 4 stretchers is a 'no room for anything else' situation. I can't fit this in my boot without putting one side of the seats down.
Zempire Evo TS - I use this for camping with myself and up to 2 children. I needed something I could put up and down solo and would be reliable. It's never let me down. It fits 3 stretchers and I can put the awning door on if I want a bit more room to store things. The optional roof does make it much darker inside but leave it attached permanently as it's a right bastard to attach solo. The TS does take up a lot of room in the boot though but I can fit it without putting the seats down. My next tent will probably be a TL if I get it soon, or the modular ones if it's a few years from now.
Dometic Pico 2x2 swag - I use this for just myself when I need to camp for more than a single night and the site requires me to carry the tent a fair distance from the car. I've never had it leak and it once held up to a week of steady wind and rain unattended on a site without issue or leaking. The inbuilt airbed sucks, get a proper mat. It's also really expensive and should only be bought if you find a crazy sale. Now I'm not saying you should get a swag - but I've been incredibly impressed by the quality of Dometic and how well designed it is (barring the mattress), so that Santorini is worth giving strong consideration.
But my actual recommendation would be - something like a Wanderer Magnitude 6 person dome tent. We have an older version that has been in use for 10 years now and it's still going strong. We got the most use out of this when it was just myself, my partner and our first child but it still gets used now. It only fits 3 stretchers so these days when we use it, the wife and kids are in this and I'm out in the swag or a hiking tent. But it packs up super small and easily fits in the boot and leaves space for the rest of our gear. It's a bugger to put up compared to the other tents we own but we've become a bit spoiled with inflatables & instant up's. It takes 2 people and it's not difficult, just time consuming. It has a big room at the front that we've used for many, many rainy weekends. We even just 'camp' in it in the back yard sometimes.
As to why I recommend it - it's cheap. You're first time campers, you don't know if it's something you'll continue with. You plan to eventually buy a camper when you have a car big enough to tow it - but you'd need a bigger car anyway for the tents you're looking at. I reckon considering getting something like the Wanderer and buy a separate gazebo. You'll save a huge amount of money. Domes can stand up to a lot of wind and rain but if shit hits the fan, go to a motel for the night. Even with a great tent you won't get any sleep at all out in a thunderstorm and everyone will be tired and grumpy for the weekend.
I bought a Coleman Instant Up 6 on the BCF boxing day sales in 2012. It's only just died. The fly ripped where the ropes attached and the UV was starting to make the seam tape brittle and fall apart. I could just get a new fly I suppose. The base is still good. Pretty happy for 10+ years use.
I started out with that Coleman Gold series tent when I first got into camping couple years ago, and it’s been super reliable for me. I’ve taken it through some pretty wet weekends and it’s always kept me dry. The setup is a breeze and the space makes it way more comfortable, especially when you’ve got a lot of stuff to keep organized.
Just make sure to practice setting it up at home before your trip so you’re not fumbling around at the campsite. Also, I think the extra space really does make a difference when you’re camping solo with all your gear.
If the budget can afford it, stepping up from the Coleman Silver to the Gold/Northstar range is a significant increase in quality and experience. Treat it well and it will last for years.
macfudd
