But the battery only lasts a few days on 4G, rather change to 2/3G in setup

I just received this phone, the dual sim, black version, ordered through HDEW. The phone looks great, but it came with a European two-prong charger instead of a UK one. There was no mention of the fact that there was no UK charger in the product description. HDEW provided a UK USB plug in the box - although with no USB cable - so they knew it would be the wrong one but didn't bother to include this in the description to buyers. This plug is not the equivalent to the correct UK Nokia charger. Sadly I am returning the item - I leave this here as a warning to other potential buyers of the phone in the UK!

As a kaios phone I would say they've done a good job. But I wouldn't compare it to the s40 phones in any way.
Just one big problem the contacts app is very slow and lagging each time, even with less than 500 contacts.
So when looking up a contact you'll have to wait 15 seconds till it loads.
The Alcatel phones which are on the same platform work much better and faster.

I boutht t'hem for family, so I haver Another kaios devices and sync calendar, perfectly. But 2720 flip and 800 though doesnt. I taller eith SOTEL, and told me to return de ítems. I "ve taller eith Nokia and Kaios systrm, but they haver no solution yet. As I ser It could be an update kaios versión, but really I cant wait months or a Year, if It was It. So the provideer has Benny very King , And I ll finally ll send the items and expecting de refund for t'he amount. I'm sad for that..they ar good devices, but Calendar os what I most Use..and eith dual Sim. As I Saïd..I haver an Alcatel kaios devices and works syncing perfectly eith t'he same account. So I've been waiting some days..for t'he upgrade..but there isnt. Finally I'll send back de ítems. What a Pity...:(