Are there any alternatives?

Yes, but most of them are more expensive:

　　$6,000 Maingear Vybe — Much more expensive and comes with a worse case, but Maingear offers more customization options.$5,000 Origin Genesis — Significantly larger and more expensive, and doesn’t included a water-ooled GPU. There are more customization options, however.

How long will it last?

You need to drain and refill the EK 275 Conquest at least once a year, but as long as you do that, it can last for a long time. Upgrades are possible, though they may not be practical if you don’t want to get your hands dirty with custom watercooling.

　　

Should you buy it?

Yes. The EK 275 Conquest is exceptionally well built, and it’s much cheaper than the competition. It also uses EK parts for watercooling, which have a massive pedigree in the community.