If you are not in the urge to buy a new laptop, you can wait for another 1-2 months. There will be more release of new models with new processor. But if you wanna get it now, imho Dell Inspiron 14 7447 DOS is still the most reliable laptop with good specs you can get with 2.8k. 
Dell Inspiron 14 7447-21454G-DOS Laptop/ Notebook (i5-4210H, 500GB, 4GB, NV GTX850M, No Windows)

Yes, you have to install the OS and all the drivers yourself. Much cheaper. But installing the correct driver might be tedious sometimes. If you feel like going for the DOS, you can always get the product key from garage sales. There are a few reliable and trusted dealer which sells it at RM60 only. 

Can, but that will definitely take time and very pricey. And if you buy the one that comes with OS, is almost the same price already. Anyway, Y40-80 comes with an i7 but a much weaker graphic card. GTX850M performs better than the Radeon R9 M275. More over, since you want a decent laptop, an i5-4200H has a higher clock speed and higher GPU clock speed than the i7-5500U. If you were to focus more on gaming, go for the Dell 7447. The onsite warranty is more reliable. But of course, the battery life in 7447 is much shorter than the Y40-80. 

You can consider this laptop too. 
Asus K501LX-DM006H 15.6" Laptop/ Notebook (i5-5200U, 4GB, 1TB, NV GTX950M, W8.1)

Dell warranty more reliable. 7447 has less storage while K501LX has weaker processor. Actually there is not much difference between GTX950M and GTX850M. If you travel a lot with your laptop, go for the Asus K501LX. It has relatively longer battery life and lighter in term of weight. Moreover, K501LX has FHD. Although you can get more specs with Asus, it has one of the worst after sales service. So, think of your priority. 

The difference between the two processors is that the i5-5200U is more power saving and is created for a longer battery life. Not much difference in gaming experience. But if you really wanna compare, K501LX has the better specs. Dell onsite warranty is the best in Malaysia so far. In within 2 working days, your laptop can be fixed. If an Asus laptop has spoiled and you wish to claim the warranty, you have to go to their shop. They will send them to their service centre. That will take weeks. 

Yeah, sometimes it's all about luck. People say Lenovo has lotsa Lemon products. But I only encounter a wifi problem once in 3 years time.

Nah, back in 2012-2013, Lenovo and HP warranty can fight with Dell one. But dropping since last year. Apa boleh buat? But still better than Asus. Asus replaces a hardware only took a month. That was what my brother told me.

Some people use laptop to work. Hence, storing important information/homework/presentation slides in the laptop. If no repair ASAP, how to continue work? That's why Dell onsite warranty is so popular.