Why would you spend three nights in Wengen then move to Interlaken?

It takes less than an hour to get from Interlaken to Wengen by train.

Stay in one place.

Thin

Well Interlaken is very different from Wengen - it's a world of difference - I love Interlaken and think it is a good base for travel around the greater Berner Oberland - from Wengen you have an hour each way to get down to Interlaken say to do a lake boat trip on either lake bookending Interlaken or to take the Brunig Pass scenic train route to Lucerne, etc.

Two very different places - like being miles and miles apart.

I'm late to this party but I MUCH prefer Vevey over Montreux. They are nothing alike imo, other than both being located along the lake. Vevey has a much more "Swiss" feel to me, the main road doesn't cut thru the center of town in the way it does in Montreux. More pedestrian streets in the center. As far as a place to stay those you originally mentioned for Vevey are wonderful. For activities, if the weather is clear, the tram up Rochers de Naye is very fun.

It is a hard decision but as PalenQ said, it feels very different in Interlaken and last time we stayed there and "commuted" up to Wengen, Murren, etc. The pro's were that we were close to the lakes for the boat trips and for other day trips plus the weather was more likely to be nice. Also, I loved the little house we rented right on the river near Unterseen - was so nice and I hope I can get it again! The con's were that we had to commute to the mountains and you lose that feeling of waking up in the midst of peaks. So, I figure this way I can use my Wengen base for the mountain days and my Interlaken base for my non-mountain days (or maybe if the weather is excellent, convert a day to the mountains). It is only the inconvenience of having to move twice but the kids are now old enough it isn't quite such a trauma and we pack really light anymore.

Thanks Suze - I am definitely going with Vevey and just sent an email off to Hotel Des Trois Couronnes to see about availability!

After that PalenQ it will be time for me to start the spreadsheet on the Swiss pass analysis!

"Btw, does anyone have experience with the scenic boat cruises from Vevey/Montreux and particularly the boat cruise that stops at Le Bouveret?"
They are just fine. Try to board a historic steamboat (marked as such in the timetable). If you have kids, a stopaover at Bouveret is a must: Swiss Vapeur Park, Acquapark.
http://www.aquaparc.ch/en
http://www.swissvapeur.ch/en/index.php

"The main road (at Vevey) doesn't cut thru the center of town in the way it does in Montreux"
May be Suze was never in the historic center of Montreux (above the railway line, close to the schools, the administration buildings and the entry to Chauderon Gorge).
But I agree: Vevey (Nestle headquerter, some industry) is much less touristic and the area around Place du Marche is fine.

I'm not sure why you'd think that. Yes of course I've been in the "Old Town" of Montreux, it's a charming section. But that's not the center of the business district, where the main road does in fact cut thru town running parallel to the lake. Very different than Vevey.

Staying in Vevey or Monreux you cannot go wrong - but if your hotel does not have a lake view in either town then you may as well be in any Swiss town.

I disagree. Just because you don't see the lake from your own hotel room doesn't mean it's not a joy to be in a town with a lakeside promonade (quai) like Vevey and Montreux both have to go out and walk along, and have the lake views as you are out & about in town.