You get a lot for your money with acer, I have bought 3 at least for others, no complaints from them and well made.
Dell - Good design and can be good value but they seem to have cut corners recently and hardware failures seem common. So consider a service contract essential.
HP seem to be good well made pcs, esp laptops but like acer and dell they put a lot of trial software on them so you spend a day or two clearing this out!
Just make sure you et what you need in terms of space and facilities plus you like the keyboard and screen!