Can brute force SEO tools like SENuke help in rankings or somehow get you penalized by the search engines?
Can search engines even "see" that anonter tool has been used to do the SEO? Is, for example, SENuke worth the money?
Yes, it can help and yes, it can get you penalized.
Those tools create lots of links to your site from "good" social media sites, links from good sites increase site ranking => Those tools can increase ranking.
Now, about the penalizing thing
So, any such tool (I don't know anything about senuke specifically) is probably worth the money, until you get caught and get penalized.
Update: everything below the line was added after the answer was marked as accepted, so the question poster may not agree with it - I just had to go back and update my answer.
Using senuke or other “brute force SEO” is spamming, it’s filling other sites with junk without their owner’s permission, it’s actively making it harder to find information by filling the internet with what is basically just pollution – it may be an effective way to make more money but so is sending spam e-mails (or dumping toxic waste from a factory into a nearby field and polluting the land instead of handling that waste properly).
Please don’t do it, it’s just evil, you're better than that.
NO. They do not help you. SEO cannot be brute forced. If you're looking for quick and easy then SEO is not for you.
Tools like that do you no good and can only potentially do you harm. Search engines can't tell if an SEO tool was used unless that tool leaves a signature behind like a meta tag or common snippet of code. But the techniques used in brute force SEO are usually black hat which is a recipe for penalties or bans. That's the exact opposite of your goals and is not worth the risk.
Any links you get from them will be low quality and nothing you can't do yourself.
Be patient. Write good content. Build your website so it is usable and accessible. Use semantic markup. Then market it. If your site is any good over time you will climb in the rankings.
These "brute force seo software" you speak of are just tools for spammers. There is no surefire way to get good search ranking other than by providing good, useful content, and you still don't get top search ranking overnight. Using content spinners and tools to submit junk articles en masse to social bookmarking sites will not improve your search ranking in any meaningful way. If you're going to spend money on SEO, you're better off hiring a good writer to write quality content for your site or getting into the Yahoo! Directory.
Just look at the type of sites that advertise these tools--they're spammy, poorly designed, with poorly written web copy, and generally have poor search engine ranking themselves.
If you're even considering using them, then good luck... Even if you manage to improve your ranking in the short-term, you're going to have a hard time retaining that position. And the more aggressively you spam your site, the quicker you'll be identified as a spammer and penalized or even dropped from the index. Furthermore, your online reputation will be permanently ruined by engaging in sleazy SEO practices.