My ergomonic keyboard has been so helpful in reducing muscle strain.
I usually just use the regular cheap ones at work. 
I used to as well, but the v shape of this keyboard is great.
Does it help with arthritis? 
Maybe.  There is one configuration that requires very little movement of arms and wrists when typing.
Are there certain companies that make ergomonic keyboards?
Typing
Typing is the process of writing or inputting text by pressing keys on a typewriter, computer keyboard, cell phone, or calculator. It can be distinguished from other means of text input, such as handwriting and speech recognition. Text can be in the form of letters, numbers and other symbols. The world's first typist was Lillian Sholes from Wisconsin, the daughter of Christopher Sholes, who invented the first practical typewriter.
User interface features such as spell checker and autocomplete serve to facilitate and speed up typing
typical straight keyboard.
An "adjustable split keyboard" has the keyboard split into several independent pieces, so the angle between them can be easily changed.
Types Contoured keyboard.
A further development of the split concept are contoured keyboards like the 1977 Maltron or the newer Kinesis Advantage line, which place the keys into two depressions set approximately at shoulder width, with function keys set between the key groups for use with the thumbs. In this configuration, very little movement of arms and wrists is required.
Types Handheld keyboards