Hi ASUSmy and thanks, now I have this AC87 router from Sri Computer, a fantastic sales guy "Hou". Basic setup at home is OK. But a few questions, appreciating of your kind support.   

1. I am not able to have Technicolor internet functioning for working in conjunction with AC87 (set as a router), how if possible ? (I am hoping that, since I am powering up Technicolor, I should use its internet functioning for additional flexibility in supporting other wifi devices functioning with internet service on the ground floor, as the modem/AC 87/Technicolor located. The powerful AC 87 to support ground & upper floors for the needs. Tk-Link power plugs to support hard corners of upper floor.)

I have AC87 hooked up between TM modem & Technicolor, modem ethernet cable "out" connecting to AC87 WAN, AC87 ethernet port 3 (selected as VOIP enable) out to Technicolor WLAN and as usual it has the dect phone working. Note that the AC87 is working, but Technicolor LED lights showing broadband/wifi/phone lines "green" (no devices are connected to all ethernet ports, and no internet LED is lighting up), but my PC can detect Technicolor wifi signal but no internet service.

2. Why AC87 is showing a low 216.7 Mbps (I used "wifi analyzer" apps), my other wifi router/extender (Technicolor, Tk-Link power plugs 4230 wifi kit) are showing 300 Mpbs at the same time ? Note that all my wifi devices (PC, notebook are not AC grade but a mix of n & g.)

To appraise AC87 powerful router, it provides a strength of -40 dB as compare to Techicolor -68 dB, power plug -65 dB (a few meters away) on the upper floor where my PC is located. Actually, the Technicolor is a good wifi router with good strength.

Good news, note also that my WD EX2 8T when connected to AC87 erthernet port is showing only "green" LED blinking. Earlier showing a mixed of green & yellow LED with green blinking of the EX2 when used with Technicolor.

Thanks

Yes, you are right. LAN speed (ac87 ethernet ports are 1Gbps) is much faster (cabled) and AC wifi "practically" is about >>500Mbps for 5Ghz, and it is better than max n <480 Mbps. I need the wifi speed in the house. Time is more valuable than small $$, sitting there for hours for a slower progress. I hope it is a right move. Hoping your review is affirmatively positive.   

Also, My WD EX2 NAS is working at 1Gbps by ethernet cable with ac87; believe it helps the wifi speed.

Hi lucklyghost, your good advice is much appreciated, many thanks.

All these devices/equipment are installed next to one another (TM modem, AC87, Technicolor, Oppo, TV, WD NAS, Chromcast.)

Actually, there are other "good" AC routers. The recent KLCC convention center was showing "yet to be available soon" Tk-Link AC router, forgot model number, about < RM600. Asus AC68 has very good reviews.

Not sure of your usage, and I am new to these technologies and experience. The fact is I am struggling to optimize the WD NAS. At times, I need to learn from you....  Cheers....

(n wifi is at best by 600 Mbps, older devices may be 480 Mbps. AC seems like > 1000 Mbps. Not sure it is right)

N66u is a very good router,and will be to support your requirements  (not too sure about netflow though) SNMP might be available with Merlin firmware. Not too sure about it,but the AC56U definitely supports it

Huge differences.
Merlin is still based on ASUS official firmware with lots of tweaks & functions that aren't available in ASUS official firmware.
In fact, ASUS official firmwares do adopt some bug fixes that is made by Merlin.
DD-WRT however is completely different.
No.
Yes.
No.

Read my post again, but this time, read it slowly & carefully.
I've arranged my answers correctly based on your questions.

Yes.
Unlike DD-WRT/OpenWRT/Tomato, Merlin is based on ASUS official firmware.
There are no differences except for the extra tweaks & bug fixes.