The main keyphrases/topics I'm targeting are made up of two words and the domains with just these two words have all been snapped up already so.... I have the option of
1. adding a third word to the keyphrase to make up quite a long domain name (>20 characters). The kws in the domain name would definitely help with SEO but just the look of it makes me cringe and think of junk sites.
2. come up with brandable names that are short, easy to remember, related to the topic but that are not a benefit in SEO, as such.
Help!
If you're joining a market that's already saturated with similar sites, and you just want to make a better version of what's already out there, you're going to find it tricky to get those all important inbounds. That's where a keyword domain can help at the moment.
In summary, no-one can answer that question except you, but the factors you need to consider are:-
1. How many similar sites am I competing with and how well established are they?
2. How easy will it be for me to obtain inbound links?
3. With effective keyword anchor text?
4. Do I really want to concentrate on SEM here, or can I consider some real-world marketing tools and/or online advertising and let the SEM take care of itself? Is my site newsworthy?
5. How much longer will the SE's give any weight to keyword domains anyway?
6. Look around the internet. See which brands are ranking and which keyword domains are ranking, and for what keywords. Unique viral ideas are easy to brand - e.g. look at the terms that Skype is ranking for (that's topicality of linking sites and brute force PR from viral inbounds at work).
Most brand domains in very competitive spaces have either been around since before the space became competitive, or have had a proper marketing budget or have just been so unique that the viral effect has taken over.
TJ
I guess someone stumbled across these niches, saw the potential and bought the domains. I'll go with the short, sweet, half brandable, half keyword name :).