New to ARM Products

I’m new to ICE tools, and I’m trying to decide which of these would be a better product over the long term for debugging ARM target boards - I’d be glad if anyone who has used such products could advise me on the following: UNetICE from Gao OR ULink from Keil I assume I would have to purchase the uVision adapter as well for debugging, but with GAO I could do that using just the one JTAG ICE. Keil allows for an OCDS (On-Chip Debugging System) interface, though I always thought the jtag port should be enough. Is the OCDS port any real advantage? Is this over parallel? Any additional advice you could provide me with in terms of the better product would be appreciated.