Both should work well.
The E4 is a good all-around camera with a plethora of (hackable)features, but it has a few flaws - namely the fixed focus(unless you get creative), softness at closer ranges(macro), and a relatively small lens for the sensor size.
However, it's still quite sensitive and produces a clean image. Not as clean as the Exx or Txxx series, but better than most dongles.
The Q1 Plus is practically the best lower cost phone dongle, especially with the Plus lens, which is a crisp 10mm f/1.0. For their sensor's size it's perfect, but in terms of noise it's basically the same.
I would say that if you don't mind using a clunky and rather fragile setup(hanging off the USB port) with a power bank(you will need one), and would rather have more extensibility(free PC app and SDK), go for the Q1 Plus. The lens has manual focus from infinity to macro, which is a plus.
If you want something extra rugged and more difficult to destroy(I doubt the Q1 would survive a drop), as well as a more comfortable package from a reputable manufacturer, get the E4-8.
However, if you have time and don't mind buying used, look around eBay for an Exx series camera. I've seen them pop up for around $900-1200 here and there, and an E30-60/bx beats both devices by a mile because of the larger lens. The raw thermal image from my T440bx(same-ish optical block as the E60) looks as good, if not better, than the MSX image from a hacked E4-8.