What gramp said really is true. all rands have good and bad examples out there. If you are inexperienced I would recommend you have an independent check done once you find the van you want. It will cost around £100 but well worth it even if buying from an independent dealer.
Theism model is a good layout for families but the bunks are small, how old are your kids? If older I would look at the Adria 542 DK. Much larger bunk beds ans generally well made. You can get sportline special editions which have extra kit on them.
As the others say really, we have a Ranger and we are very happy with it we have had a few Bailey vans and have never had any problems with any of them. There can be damp problems with all vans which is usually in the front or the rear panels have a good look up the sides where the rails go round if you see tiny hairline cracks which may even look like scratches be cautious as water ingress is likely, it would be best if you are unsure to have it inspected search MCEA and I am sure there will be an engineer near you
------------- its our imperfections that makes us perfect
We've had 2 rangers. A 1999 510/4 bought 3 years old and a new 2010 520/4. Both were well equipped and comfortable as well as light enough to tow with a 'normal' car. We now have a Pursuit which is the present day Ranger replacement model, again bought new.
Didn't have any big problems except the 510/4 which had floor delamination in the bath room which was repaired for about £100.
Bailey are a big manufacturer and there will inevitably be some problems but also thousands of happy customers. I've always found them easy to deal with.