My perspective though is that it wasn't a bad spot, not as convenient in some ways as living closer to downtown Basel as I do but also, I think with kids and dogs, depending on the location of the home in question, it seemed pretty great.
The flat my b-i-l was in was a bit more like a townhouse, maybe four per building, two ground floor, two upper. They had some common area space between the buildings where I saw children playing. The location of their flat also was within walking distance to a doggy vacation home and a farm with free range chickens (which means really tasty eggs available quite often).
I never saw really what "downtown" Therwil was like as I was usually just passing through.
One nice thing about Therwil is that there is a huge boarding kennel. Many here have used them. Hundeferienheim Forellenbach is the name.
It's a bit tricky to find if/when you need it, but it is convenient to Therwil.
There's also a HUGE (by Swiss standards) Coop grocery store in Oberwil. Which is just up the road from Therwil.
If you're looking to live out that way though, I'd recommend Dornach, Reinach, or Aesch which are much more convenient to a motorway and also the tram lines.
I've a mate living in Aesch, was taking him the best part of an hour to get to work at Novartis by tram, by car, 15 minutes.
My family and I moved to Therwil a year ago and we're happy here. My eldest two children have settled well at their local school and Kindergarten, and both play for FC Therwil. We have a playground just round the corner and there are plenty of green areas around for walking, bike riding, jogging, dog-walking etc. We have a lovely house with a garden all around it - a luxury you can afford when you choose to live slightly further out if Basel town centre. My husband gets to work (at Novartis) in 45-50 mins by tram but also goes by car or bike some days which is quicker (depending on the time of day).
Therwil has 8 Kindergartens, 3 primary schools, a secondary school, and a couple of Spielgruppe (pre-schools) from aged 2. There is a Co-op, another little supermarket, a garden centre, a couple of chemists, a couple of bakeries/cafes, a couple of bike shops, a second hand children's shop (toys, clothes, shoes, pushchairs etc), a stationary shop, a wool shop, a shoe repair shop, a tanning studio, a little bar, and a few other random shops. There are also a few restaurants. There are several doctors (ours speak great English) and also several dentists. Therwil also has the Ahead With English school/preschool (see their website www.aheadwithenglish.ch ). It has football, baseball, gymnastics, athletics, tennis and handball clubs (probably more too but those are the ones I know about).
There are two tram stops in Therwil (with the number 10 tram) and it takes about 25 mins from here to get to the Theatre tram stop in Basel and about 20 minutes to the zoo. It takes 4 minutes by tram to get to the tram stop for the huge Co-Op this side of Oberwil (Huslimatt) or you can walk there (going passed an ALDI and a McDs on the way). The number 61 and 64 buses also go through Therwil on a regular basis. We find it easy to get to most of the places we want to go to.
Well I hope you've learnt a bit more about Therwil now. Like I said - we're happy here. I think finding the right house for your family (inc. dogs) is probably the main thing as that's where you'll spend most of your time. I suggest having another look at Therwil if you've found a good house there and then work out how long it'd take you to get to the places you'd need to go.
Good luck with your search!
Hope you find somewhere,
Hazel