The Crye NightCap is a very good solution. They work well. I also have had very good luck with buying Airsoft Clone Helmets of the Maritime Helmet Style and then rigging them out correctly. Rigging them out correctly means:
1. Lancer or Atairsoft are just as good as any of the "Big Name" Bump Helmets, but much lower in price.
Amazon.com : Lancer Tactical Medium - Large Industrial ABS Plastic Constructed Maritime Helmet Adjustable Crown 20mm Side Rail Adapter Velcro Padding Stickers NVG Shroud Bungee Retention - A-TACS Foliage Green : Sports & Outdoors
www.amazon.com
Amazon.com : ATAIRSOFT Adjustable Maritime Helmet ABS Multicam MC for Airsoft Paintball(L/XL) : Sports & Outdoors
www.amazon.com
2. Installing a 3 hole Ops Core Type VAS shroud. I have had very good luck with cheap Amazon "Chinese Shrouds" that perform just as well as the "real Ops Core VAS shrouds" that I have found to be somewhat sloppy and irregular as well. I actually think they get the Chinese to make them for them. For both the "real Ops Core" and Chinese clone copies you sometimes have to shim the inside of the surfaces with a little bit/sliver of electrical tape to take up any slack/chatter with the inserted mount. No big deal.
Amazon.com : NEW PHALANX FOLIAGE GREEN MARSOC/WARCOM night vision 3-hole mount pattern NVG Shroud : Everything Else
www.amazon.com
3. Install a H Nape 4 point Chin strap. Again, the Airsoft cheap versions are just as durable and good as the "real stuff".
Amazon.com : AIRSOFTPEAK Airsoft Helmet Chin Strap for Fast ACH MICH Tactical Helmets, H-Nape Suspension System, 4 Points Chin Strap with Bolts and Screws, Tan : Sports & Outdoors
www.amazon.com
4. Now here is the most important. Buy the Deluxe 4 D Helmet Pads from TNVC. That is the best $100 bucks or so you will ever spend on a helmet.
The Most Comfortable Helmet Pad Set Available ***READ COMPATIBILITY NOTE BEFORE ORDERING***
tnvc.com
5. The best mount out there is the Norotos Rhino 2 with a Dovetail Socket installed on it. Go to Fleabay and you can pic up new Rhino 2's from say $55 to $80 bucks and then put a dovetail socket on it. Go to TNVC for Nortos PVS 15/18 Dovetail Socket for $54. So you usually can rig the Norotos Rhino 2 Dovetail up for around $125 vs buying it already assembled which will run you about $325.
PVS-15/ PVS-18 Socket for Norotos AKA2 Mount
tnvc.com
6. Now if you ever think you might buy another PVS 14 or Breach and want to run dual NV or NV & Thermal, you are money ahead to go on and buy the $350 Mod Armory Lite Weight Bridge mount. Point being a Wilcox G24 mount is $500 plus the Wilcox J Arm is $200 for a grand total of $700 for mount and J arm that only allows ever running one device. You are better off buying the Mod Armory Light Weight at $350 and just take one of the arms off while you are running single and if at a later date you buy another 14 just put the arm back on and you now have Bino's.
7. To finish out the helmet scenario above you would also add a TNVC Mohawk and appropriate counter weights depending if running a single or duals.
Now if you just go with the Night Cap, I still recommend the above 3 hole VAS Shroud and the Norotos Rhino 2 with Dovetail and Mod Armory Light Weight Bridge Mount. They all polish out the Night Cap very well. When you go down the NV & Thermal rabbit hole it really helps to learn how to stretch dollars while still maintaining excellent performance. Some places you can cut corners and be ok, others not so. Buy good solid NV & Thermal devices, then you can usually save some money by prudently putting together the accessories. There is a lot of "Mr. Cool Guy Operator Advice" out there that is more designed to take your money than really make you effective.
Hope this helps you in some of your choices & options. IMHO it pays to really study, learn and think about assembling your setups so that you become knowledgeable and spend your money once and wisely.