Final Thoughts
Asrock has displayed plenty of ingenuity with its Mini PCs over the last four generations, with every model from the Ion 330HT to the Vision HT 300 bringing big improvements, often including a full chassis redesign or at the very least some major tweaking and Intel's latest parts.
The Atom 330-powered Ion 330HT was blown away by the Core 100HT, which could be outfitted with a mobile Core i7. The Core 100HT was eventually trumped by the Sandy Bridge-based CoreHT series, and those models were replaced by the Ivy Bridge-based Vision HT 300 range.
Naturally, this year's Vision HT 400 series has moved on to Haswell's mobile processors, though being that Haswell doesn't bring too much of an improvement over Ivy Bridge, we assume it was hard for Asrock to justify creating and marketing something entirely new. So it didn't.
Besides stuffing Haswell in a Vision HT 300 chassis, the Vision HT 400 series also adds a few extra USB 3.0 ports, MHSL (Mobile High Speed Link) and an updated Wi-Fi solution, but it's a relatively minor update that is simply intended to extend the life of the preexisting series.
At the end of the day, what really matters is whether the Vision HT 420D is worth its $660 asking price. That seems relatively expensive, especially when you tack on the cost of an operating system. By our estimates, Asrock is charging a $150 to $200 premium for the Vision HT 420D.
A Mini-ITX desktop with a Core i3-4130, an Asrock H87M-ITX motherboard, 4GB of DDR3 RAM, a 1TB 2.5" hard drive, a USB Wi-Fi/Bluetooth dongle, an MCE Remote Controller and a decent case with power supply could cost a little under $500, though this system won't be as compact.
Unfortunately, that's more of a negative for the DIY HTPC and less of a positive for the Vision HT 420D because Asrock's box is around 90% bigger and potentially more expensive than a similarly-equipped Intel NUC. We can't help but feel like Asrock needs to hit the drawing board again.
It's clear that competition has heated up since Asrock's first Mini PCs arrived and we think the Vision HT 400 series would have more appeal if the company found a way to cram a desktop chip inside. Perhaps the answer is a fanless case like the Akasa Euler we used in this Thin Mini-ITX build.
In the meantime, the Vision HT 420D is a decent option if you don't want to get your hands (too) dirty with assembly, if you don't mind buying/installing an operating system and ideally another stick of RAM, and if you value a little flexibility with secondary 2.5" HDD/mSATA SSD storage.
score
Pros: The Vision HT 420D is relatively clean and compact with plenty of HTPC-friendly features including Blu-ray support, a remote control, Asrock's spin on MHL and Intel's Haswell architecture.
Cons: At $660 without an operating system, the 420D is somewhat overshadowed by DIY options with more power for less cash as well as Intel NUCs that offer similar specs in a smaller package.