First of all I don't recommend ACER to anyone, I don't know but the performance is not that good. ACER was until a short period of time part of different companies. They become what we call ACER recently compared to other giant companies.

If you still want to buy the ACER Laptop, make sure to buy [International Warranty]. If you don't have this one here, they would be sorry to tell you to bring or you would be paying for every service you require.

I prefer HP, it is a descent and very good laptop compared to other laptops. The performance and prices are good and cheaper compared to the others.

Dell is a very good one, but everyone knows that Dell customer support or service center is simply bad.

MAC, is like the guys here are saying: When you get MAC, you can't go back. I've installed MAC OSX Tiger on my laptop [The version that works also on PC] and I was like, ... wow so how about it running on a real MAC laptop?

The prices:
The prices are different because of the difference specifications and operating systems including. The new laptops would be a little higher in prices than the usual ones and the secret is in Windows Vista. Look at 2 HP laptops with the same specifications and you will find that there is a difference between the prices because one comes with 'MS Windows XP Home edition' while the other one comes with 'MS Windows Vista Home Basic or Premium'. The difference would be from 500 - 800 Q.R.

Another factor is the processor, the speed and type of processor can also play a major role here.
We have currently those :
1- Centrino Mobile Technology
2- Core Duo
3- Core 2 Duo
The price would go higher as we move from Number 1 to 3 [No.1 is the cheapest]. I'm talking here about the good ones along with some AMD models. There are a lot that you can find with cheaper prices, those got Celeron, Sempron and other low cost processors.

The RAM, Hard Drive capacity and the size of the screen [usually 14, 15, 17] and Video Cards [Shared or not, don't go for the shared or what called VRAM, those would rely on your laptop RAM so if you have 512 MB and your Video Card was 64 MB, then the actual RAM that you have would be 512-64=448 and so on] can also play a role here in determining the prices of your laptop.

It is in the end up to you and up to what are you going to use your laptop for. It can be for gaming, programming or just surfing the net and do some Ms Office work.

I can't cover everything here, but that was a general idea.