So I am sick of most smartphones on the market, so I was thinking of getting something a little older, an old N900 and maybe swap its OS with a different OS or upgrade its OS if possible. I have little knowledge about this so how easy would it be and is it worth it?
N900 and HTC HD2 are legendary, but they're old now, and I doubt you'll get a satisfactory experience with them.
There is a lot of exciting choice now though. The Ubuntu Phone, cheap and decent, not high end (which is a waste of money anyway), but works pretty good. Then there is the new Microsoft 640 XL (not Nokia any more, the real Nokia has now also started producing mobile devices again, the first one being the absolutely great Android tablet N1, but there will soon be smartphones also as the contract with Microsoft has now expired), which I think is a great deal for people that want a phone and not a phablet (and don't live with the illusion that phones are private or secure), and don't care about the cloud crap, but care about a decent camera, a long battery life, and good price. There is the Huawei Honor series, which is simply great and also available at a decent price, and the next Nexus will again be produced by LG, so probably will again be a better one than the HTC Nexus 6 that is such a failure. Also Samsung has some pretty nice midrange phones.
Yeah the HD2 was legendary, but I just want a cheap phone that is decent as I do not really do much, most demanding thing I do is browse web and music but phone reviews seem rather biased these days, I'm just sick of Android and the crap with the battery issue in 4.4+
You can try some of the old Blackberry models. I am planning to buy the Bold 9900 because I prefer physical buttons instead of touch screen. And then there is One Plus One which has the specs of a flagship phone and it cost about half the price of the other common "smart" phones.
Thing is I use contracts to pay for my phone as I need the texts and data, I would go with Blackberry but I don't like the idea of the company going under, I used to follow RIM and I started to worry when the BBM phase happened in the UK (Kids got BBs because of BBM been cheaper than texts). But I do like the idea of a different OS that is professional and secure. I have also just seen that RIM wont make another OS after 10, but continue to support the system I presume with security, a sad and worrying through which is a major tick away from blackberry. I do hear Windows phone is the most security mobile OS due to its low installed base (This is obviously a given, the source was Mikko Hypponen.) Android is just plain crap to me these days, I currently own an Xperia Z and while the hardware is excellent the software is awful, I have had to ROM to CM12 so I can actually get Android L, the software in 4.4 from sony is bloated, out-dated and tracks data (Understanding a phone is basically a GPS device that can make phone calls.), If i could move the Xperia Z to a different OS it would be brilliant its still a extremely quick phone and has a lot of power under the hood.
The day before we went to USA last year i broke my Samsung Galaxy S4 in an attempt to Encrypt it before going over there, i had no time to fix it so i had to take my trusty old N900 with me :) it has all kind of pentesting app's on it, but it worked great, the camera is really bad compared to my GF's Iphone 5, but it did hold batteri alot better than my normal phone, i dident really use it for much other than seeing the time, texting and playing SuperTux :) i still have it, now with my GS4 as backup phone, so im only keeping the N900 for the pentesting and all around fun you can have with that lille machine :)
Best thing to do is see how much you actually use. Usually you can half your full contract price and that about how much you should end up paying for similar allowances. Three give 4g on all there sims but usually not unlimited minutes unless you pay a little more but there quite good for data. Vodafone are bringing out volte and voice over WiFi the is summer as well
How about the Jolla Phone with Sailfish OS? The guys behind it are ex Nokia employees that worked on MeeGo and Maemo, it could be what you're looking for.
I was considering this also, its a nice phone and the specs will fit fine, as I said most demanding task is either spotify or web browsing, side loading is also a nice feature, works out about £191 for me inc delivery so nothing to bad
I was looking at the e 4.5 for that, I would only really need to hack Spotify onto it. Its a cheap and cheerful phone I think so its a toss up between the e 4.5 and the Lumia 640 both nice phones although e 4.5 again is Linux XD