I went last year - very pleasant event and if the weather is good a relaxing family day out / picnic venue.
Unfortunately will not be able to go this year as I will be in the IoM - first ever trip to watch the TT races!
Enjoy! I'm sure you will have a great time. The IoM TT is one of the few genuinely unique races in the world. I went there from 1978 to 1994 without a break and have some tremendous memories. Not sure where you're staying, but I always found spectating in Ramsey to be quite versatile; quite a lot of different corners in easy reach and a lot of them reachable during the races. Having said that, my knowledge is over 20 years out of date, so things may well have changed...