@Amy:
Depends. Just in the ultraportable category (under 1.5kg), prioritizing performance only, that is with lastest gen quad-core ULV chips,
1. Traditional Clamshell
$600 ($450 in parts of US if you can find it) - Huawei Matebook D 14 - R5-2500U / Vega 8 / 57Wh, 1.4kg. This is the best option if you're okay with non-upgradable 8GB memory.
$800 ($700 with holiday coportate discount) - Lenovo Ideapad 720s 14 - i5-8250U / MX150 / 55Wh, 1.5kg.
Same line as this Zenbook 14 and best ultrabook with dGPU for the money atm. Released more than a year ago, nothing since has surpassed it. Compared to the Zenbook it has better build, dual separate fan cooling, better keyboard, touchpad, ports with full SD, TB3 and USB-C PD, upgradable RAM, WLAN and faster PCIe x4 SSD. Only drawback is that RAM runs single-channel, but ~5% GPU performance drop is a fair trade for serviceability.
2. 2-in-1 Convertibles
$700 - HP Envy x360 13 - R5 / Vega 8 / 53Wh / 1.3kg. Again, good value because Ryzen.
$800 ($700 with same discount) - Lenovo Yoga 730 13 - i5-8250U / 48Wh / 1.2kg. Best 2-in-1 ultrabook for the money and also the cheapest laptop in the market with PCIe x4 lane TB3 ports. Has dual fan assembly which produces excellent sustained performance. RAM is soldered but 16GB is configurable for more. This is absolutely the laptop I would buy If my budget was limited to $1,000.
Lenovo 500 and their Thinkpad E series are solid mid-range value options, especially with the discounts. ~$500 range
Asus Vivobook Pro/Slim and Acer Aspire/Swift/Spin series are decent value but mostly heavier and worse in every other aspect. Worse service after purchase, low availability, and low discount rates. And they have so many model variations and complicated names frankly it's not worth evaluating.
Finally, stay away from anything else low-end including but not limited to - Dell Inspiron, HP Pavillion, Lenovo 300, HP Probook, Dell Latitude 3000 etc.