I am looking to come up next saturday (21/6) using the direct train link but have heard there have been regular cancellations since the service was launched. Anyone used the service or have any feedback to offer?

Never used it but...

Everyone I have spoken to have had their train cancelled regularly and stopped using it.

Lady I work with had 2 trains cancelled on Sunday from Kings Cross to here, ended up staying in London overnight & having to use an additional days holiday

Not had good reports

When I go from Doncaster to Hartlepool by train, I always go via Newcastle. Less changes and not much difference in time. I have never tried the new service yet, but would have to change at York or Northallerton in order to do so, as it doesn't stop at Donny. In fact it doesn't stop anywhere south of York. Another problem Grand Central have got is the age of their stock, hence the number of breakdowns.
The best solution is for someone to pick you up at Darlington if that is at all possible.

One less change but wouldn't it take you another half hour to an hour.

I know what I'd choose!

It depends on the times of the trains obviously. I have been travelling up to Hartlepool by train for a lot of years now and currently I prefer the Newcastle option, having tried them all.
There used to be a train from York to Sunderland, calling at Hartlepool, but that seems to have disappeared in favour of this new one. The only problem was that it called at Middlesbrough as well. It takes what appears to be an age from Darlington to Hartlepool via Thornaby. Donny to Newcastle is an hour and a half and a further forty odd minutes to Hartlepool. There is not that much difference in time using Newcastle and you cut out what seems like an eternity on Thornaby station. Personal preference I suppose.
Coming back, from a match say, I get the first train to arrive at Hartlepool station and follow that route.

I like travelling by train, especially on the continent.
One of the best journeys in the UK is the train from Glasgow to Mallaig......well worth doing.

It really does saddens me to say this as I was really looking forward to a quality train service from this town into Kings Cross. Quality it isn't - I've been left stranded a 7 times and gone back to using National Express from Darlington. My advice don't use it

cheers guys.
At £67, it was a cheaper option than via Darlo as I haven't booked up early enough. Defo not going to risk cancellations so think i'll drive.