for programming on the go, office work and browsing the internet I currently use a Macbook Air Mid 2011.
I am happy with the form factor and battery life. All I ask for is more performance. I can't really find a solution in the current Apple line-up and therefor need some advice.
So far I quite like the Razer Blade Pro 14 (2015). Linux compatibility would be important. Any tips?
I have a ThinkPad T410 from 2010. The CPU and GPU are showing their age, but I've been able to upgrade the RAM (maxed out at 8 GB) and storage (768 GB of SSD across two drives [I removed the optical drive]) to the point that it continues to serve me adequately. The only things it struggles on are Google Hangouts (weak GPU) and VMs.
In the ThinkPad world, that means sticking with the T-series or X-series rather than the X-1 Carbon. For Macs, it means sticking with the Macbook Pro instead of the Macbook Air, Macbook Pro Retina (it's my understanding that it's difficult to upgrade), or standard Macbook.
The only downside (other than a bit more weight and thickness—not at all important to me) is that for some reason the bigger laptops tend to have worse screens. In both the Macbook and ThinkPad lines, the best high-DPI screens are found on the thinner, less upgradeable machines. The best option I've found is the ThinkPad T450s, which looks to have a decent highish-DPI option. Hopefully this situation is changing (or perhaps has already changed—I'm not familiar with the newest Macbooks).
ThinkPads run Linux exceptionally well. I've never had any compatibility issues with my T410, even when it was new. Staying with Intel graphics does help a lot.
I am using a late 2008 Macbook (Unibody Macbook 5.1) for the same sort of activities you use it and find it fine and that is worrying me a bit, I use it about 6 hours a day for my personal projects and entertainment. It originally came with 2GB RAM which I upgraded about 5 years ago to 4GB, then a couple of years ago I upgraded it to 8GB, which is the maximum it takes. I also replaced the 160 GB HDD hard drive with a 256 SSD, I replaced the battery once, and had to change the power adapter too. I've also upgraded the OS from Leopard > Snow Leopard > Lion > Mountain Lion > Mavericks > Yosemite. To be clear it's an original 'Macbook' which was phased out as a brand and recently (today actually) been reintroduced as the new 'Macbook'. The processor is an ancient Core 2 Duo 2.0 GHz but somehow I can keep managing to working on my Node.js, Xcode 6/Swift projects alright.
I believe your Macbook Air is not upgradeable in the same way as my Macbook so this is perhaps the reason you are finding you need more performance. I'm not trying to suggest you don't need a new machine by the way, I am genuinely interested where you find performance becomes an issue because even though I am happy with my laptop some of my friends can't believe I am using this laptop as my primary (and only) machine so I do feel a bit insane sometimes. I once thought it may be that I've just gotten used to the slowness and don't notice it but I do use a high end desktop at my day job for C++/C# dev work on Visual Studio, and used the latest laptops at the Apple Store but only for browsing so it is hard for me to compare dev work.
I really hope I'm not spending twice as long as everyone else compiling or doing other processor heavy tasks and just got used to it, that would be pretty stupid. Even the new Macbook 2015 which has what is considered a weak processor by the press has better benchmark scores than the processor in mine. Perhaps I'll go from my old Macbook to the new Macbook.
Razer Blade seems to have linux compatibility issue. plus I don't want nvidia graphics card, always causes troubles in linux.
The Toshiba Portege R30 has a 13.3" screen, has a quad-core CPU option, and it's lightweight, but don't ask me about its quality or ability to cool that CPU. I've heard good and bad things about its keyboard.