We don't do much voip at all. Is this Grandstream voip pbx any good. It seems to be an asterisk system in an applicance? Any reviews from other forum members?

Grandstream is just a repackaged Asterisk, as the folks at Grandstream will readily admit. It's a decent set-up for a relatively low price, but you do get what you pay for. It doesn't seem to like to play with analog phone lines very well, and can be a bit clunky and tedious to provision if you have more that twenty extensions involved. Not an outstanding system, but not a lousy one either. We've installed several lately with no major problems.

Grandstream is very good in my book if you get the right size server for the right network and use nice switches like the HP Procurve. You have to have a SIP trunk provider that works with it. Not all sip trunks are the same, stay away from Vitelity even though they are tire 1, and DID FOR SALE also no good. If you need support from the manufacture then they may not be for you. Support is slow only through email and although they nail it for me when I have a problem beyond my capabilities like reading the nitty gritty of a SIP header.

I've worked with Grandstream on nation wide networks and they are very reliable. Although with a large network Avaya is probably the best way to go if your customer can handle the cost

I've done several Grandstream systems, never had a good experience.

VoIp can be a pain...the only thing I dont lile about Grandstream is support. I had a sip trunk start failing over so i did a call capture..uploaded it to Grandstream and they got back to me the next day with..uncheck the box...it worked but how did it get checked in the first place..none of my other trunks had the box checked and they all had been up and running for months

Look at CQ Simple Nimbus. It's Asterisk/FreePbx. System sizes from 10-1000 users.
Unlimited Warranty and No License fee.
Tech Support is what it should be.

https://www.cqsimple.com/

Just another data point:

My Grandstream experience was fairly awful. This was a few years ago so maybe their gear has gotten better. I have no interest in finding out!

The phones looked nice but were poorly made. The phones had firmware bugs that GS did not seem interested in ever fixing, and the bugs kept some features from working. The PBX puts a pretty interface on Asterisk, but that was buggy, with features that didn't work, or simply were not offered. Support from them was often not helpful and often incomplete. So you are at the mercy of the users' forum which, while helpful, is just a lousy way to support a product IMHO.

My advice: Avoid Grandstream.