There are loads of other options out there and the question is probably best answered by someone local to you (as the popularity or otherwise of most networking groups is often a local/regional thing). When I joined 4N I was already a member of BNI (although that chapter has now closed) plus BizLinx at lunchtime (worst £1100 I ever spent frankly) plus the various independent networking groups in Oxfordshire.
Think on this as well Mark. Have you been using your 4N membership enough? You could have attended a whole load more 4N breakfasts in the time you've been a member - which is what I did when I first got started.
Also, you have asked some questions on here, particularly about the size of businesses you're trying to get to, and then don't seem to respond to the answers which are given. Get stuck into the forum in a different way, don't just start posts that are about your business, involved yourself in other people's discussions too. Did you even read the post where several of us are connected to businesses with many thousands of employees for example?
As with any other marketing activity - what is working for you - you should be doing more of that.
In my 20+ years of all genres of Networking I have determined, sadly, that only 20% of members of ANY network implement the training/coaching/mentoring/advice provided by the organisers and team leaders.
This 20% also end up with 80% of the Quality referrals generated by the networking group.
Give me a bell anytime if you want to discuss this further
My suggestion would be to get clear on who it is you want to do business with first.
Then consider the following:
1. Where do those people hang out? By that I don't just mean networking events, but what other types of events do they go to, what do they read, where do they go online - and look at how you can be present in those places
2. Who already has a trust relationship with those people? By identifying these people and building relationships with them, you can leverage their relationships giving you a faster result than trying to build relationships directly with your target market on an individual basis. For instance, if you had a product that was of benefit to people who worked out, you might consider building relationships with personal trainers. The personal trainer will be trusted by their clients so building a relationship with the personal trainer gives you access to his clients.
3. Where do these people hang out?
Also, consider putting on your own events. My first business worked solely with IT companies. In the days when BNI was pretty much the only show in town, it was difficult for me because their format only allowed one technology company per chapter - so it was a very slow slog getting contacts. So I started my own network that gave tech companies an opportunity to network with each other. It delivered great benefits to the companies who started collaborating on all sorts of projects, but also gave me a very soft introduction to them. There's an accountant up here who has a monthly social at his house for people he's met networking both offline and online. They're proving very popular and raising his profile immensely.