Until they can get get an oss version of all the firmware it's just as secure as any off the shelf laptop with a clean install of the OS of your choosing.
If you want more security get an old Lenovo/IBM think pad mod the bios chip and get libreboot.
The cpu, graphics card, hdd, Ethernet and more have more lines of code in them than your OS kernel most likely and that code rarely gets audited even internally.
You can get a decent core i7/i5 OEM laptop made for about 500$ these days http://www.alibaba.com/product-detail/Quad-core-ultrabook-i7...
Add to that some case customization and build in their specific features like wireless "kill switches" (AKA that switch all laptops used to have when wireless used to cut your battery time by half and you needed to use them on planes) and you can still get it made well under 600$, 250-300% markup is very steep in the current hardware industry.
The OEM vendors don't make this in some basement in Shenzhen it is done very professionally and the level of customization that those laptop give the user is unparalleled today.
The PCSpec laptop's I've seen are about the same quality as my Dell XPS 15 (2014 model), some of the Macbook Air style laptop's (https://www.pcspecialist.co.uk/notebooks/lafiteII/ a UK startup that my friend works in bought this for the 20 or so hires they got once they got out of the incubator they are pretty flawless) I've seen are almost indistinguishable from Apple (with the exception that they are usually not unibody) and if you stick an Acer logo in the front and call them the C97somthing I would not be able to tell that this wasn't a brand product.
Now don't get me wrong if you pay peanuts you'll get monkeys but if you are paying 500-600$ for an OEM laptop you will get good quality including IPS screens and capacitive trackpads with large enough orders (10-20+).