It's harder, especially at first. ...but in a different way. With IOM TT the hard part is learning the track. The bike physics are dumbed down though and it'll let you away with murder. In GP Bikes the hard bit is riding the bike. It'll highside, lowside, wash out, develop tankslappers... ...and you spend a lot of time in the pits tweaking suspension and getting the gearing right for whatever track you're on. But it's much more rewarding when it all does come together. Try it for yourself. The demo gives you Philip Island and a Moto 2 bike. https://www.gp-bikes.com/?page=downloads Be aware that the full version doesn't get you any more official content. You just get a licence key that unlocks the ability to join online servers and install mods. ...but some of the mods are a lot better than the official content anyway. h106frp's 916 round the laserscanned Nordschleife is easily the best motorcycle gaming experience that I've ever come across. There's a new game version out in the next couple of days but I wouldn't let that stop you trying Beta17 today. Updating the demo version is as simple as deleting the game folder and installing the new one. Go easy on the downshifts, Beta18 is all about a major rework of the slipper clutch which at the moment is a little harsh to say the least.
I didn't say easy Forgiving would be the word I'd go for. Have all the rider aids turned off and still the only form of crash I've had is running off or into things. Have you tried turning down the sensitivity in the left and right turn options? I was all over the place at first until I cranked it down to -5. ...and I'm using a joystick - if I was using the little stick on a pad I'd maybe even go down further with it.