Day trip to soller is enough imho, maybe one night. Palma is much much bigger and more to see.
will you have a car/be able to drive?
maybe have a look for an agroturisme for a night or two if that might interest you? (I’ve always wanted to try it but never managed for some reason)
I love Soller but would agree that there’s not much to do if you’re not into hiking. If you are there’s probably no better place on the island. Even the relatively short walk to Deia (3 hr) is fantastic, and there are regular buses back to Soller. I’ve not been to Taormina but I get the impression it’s rather different, not super touristy or expensive.
I don’t know what the fuss is about with Palma, easily my least favourite of the Spanish cities I’ve visited.
The best bit about Soller (IMO) is the train ride there and back. We went early, stayed for a short while, then got the train back in time for afternoon beers and dinner in Palma.
I really like Palma. Super close to the airport, can fly there from City, nice places to eat, good stuff to see (the modern art museum is great). Perfect spot for a few days away.
I normally stay just up the road in puerto pollensa which is lovely, loads of great places to drink and eat and really chilled. Very family friendly.
Let me know if you want any tips for places to eat/drink of you go there.
Went to the market in the old town of alcudia a week last sunday, fucking biblical rainfall, absolute washout 
Love palma, have never spent the night here but have spent many days there. La Rosa and el camino are my favourite places to eat there if you’re interested. Loads of other great wee bars and restaurants/tapas places.
The wee old school train from palma to soller/port of soller is lovely.
Both soller and port of soller are lovely but i wouldn’t spend maybe more than a night in either.
Deia is gorgeous but it’s so fucking busy man, sack deia and go to valldemossa which is about 15 mins away. Fucking gorgeous wee town and again some lovely wee places to eat and drink. Would highly recommend Es Taller if you go there.
Fucking adore mallorca 
The other really good thing to do in Soller is to go to Can Prunera, which is a lovely art nouveau house/gallery
The botanical gardens are nice as well, and a tram trip into Port Soller can all be done in one (long) day trip. Book your train tickets in advance though.
Hi! We’re planning to go in early September but really not sure where to stay by the beach that isn’t driving an hour away then back?
Want to do the following:
Beach place for 2 nights
Deia/Valdemossa for 2 nights
Maybe Soller for 1 night
Then Palma for 2 nights (maybe sack of the Soller night for another Palma night??!!)
I wouldn’t bother staying in both Deia and Soller, they are so close to each other (you can walk between them in 3 hours). I love Soller, but my main motivation for visiting Mallorca was walking in the mountains.
I’m not a fan of Palma, but I think I’m in the minority on that one. I just find it dirty, traffic-choked and very crowded.
Maybe we’ll go up to Pollenca and stay there for a night. Mainly because there is a gluten free bakery there but can tempt my husband by saying we’ll go to a winery 
I thought the best bit about Soller was the train journey there. We went there and back in a day - a really lovely journey and well worth doing, but there is so much more to do in Palma. But depends on what you’re after I suppose.
Love pollenca and puerto pollensa (heading there in a few weeks). Loads of good places to eat in pollenca and some lovely wee bars. Also good to walk up the calvari steps and have a cold drink at the top and enjoy the views. 
Deia is lovely but so fecking crowded these days, big fan of valdemossa, much prefer it to deia.