High-end makeup definitely has it's advantages. As with most things in life, the more you spend, the higher the quality will be. Makeup that costs more often has a better formula that properly adheres to your skin, you can usually tell if it's going to match your skin tone without much question, and it will most likely last longer.
That said, the sticker shock for these products can be quite extreme. I personally made a trip to Ulta and just about died when I spent fifty dollars on two products, but those products (a bareMinerals primer and an Urban Decay makeup setting spray) have made my skin look better than it has in years. I would consider those products to be well worth the money.
However, to combat the high cost of those two products, ALL my other makeup products are drugstore brands, and I have been extremely happy with them as well. Revlon makes eyeshadow palettes with nearly identical colors to the infamous "Naked" palette for a fraction of the cost. Maybelline's BB cream's formula is well respected for having a better formula than higher-priced BBs. Most drugstore brands these days are conscious to create high-quality products in order to compete with high-end brands.
If you LONG for the high-end look but simply can't afford it, searching for "dupes" is very advantageous. If you see a lipstick, foundation, or eyeshadow from a high-end brand that you would like to try, see if you can match the color or the formula in a low-end brand.
The great thing about both high-end and low-end makeup is that nearly every brand produces coupons that can help you save money. Ulta has coupons and sales every week, and there are often brand-specific coupons for high-end products that you can find online. As far as drugstore makeup, Walgreens has buy-one-get-one-half-off sales every week, and Target reduces their makeup prices all the time. The legwork can be annoying, but the savings are remarkable.
In the end, it's your skin and your budget and your preference and your choice. You may have to put some work and experimentation into it, but the results will be worth it!