I don’t think there’s will be some impact to your website when title tag is used with comas, hi-fens, colons! Google works on semantic search! So better concentrate on the relevance of your content in Title, Description and Body! Let them be unique and meaningful to what you say in your page!
Oh course there will be a difference, they are different title’s after all. As to how much affect one or the other have on ranking? I’d say it’s negligable … go with whatever you think looks best.
placing your k/w in title is a good thing and will definitely get the benefit to your k/w…you can place more than one by putting a pipe signal …but keep in mind that only the k/w most suitable to your page must be put there and not to make a very lengthy title which loses its value…
They are differ and have different impact in SEO. Basically Title is used to let search engine know the most suitable keyword for your site. Using comma and hypens create some impact in search results.