We've stayed in the Radisson a couple of times. We were driving so the shuttle was not a problem, we drove ourselves to the park each day. Breakfast was really good, there was a good selection, not too crowded, the fresh orange juice and the muffins were real favourites. The rooms were big and comfy, and quiet.
The Hipark Serris is our usual hotel... We really like having our little apartment, it means our daughter can go to sleep in the bedroom and we can stay up and watch some TV before going to bed, we're not all crammed inside a hotel room. We also like being able to cook our meals, we usually have dinner there (easy things like rice or pasta), but it means we can save a bit of money. The Val d'Europe is really close, if you need to do shopping (or want to go to the restaurants there, they have some nice choices!)
The rooms are not all in top shape, we've had some issues particularly with the shower heads or taps, but more inconveniences than real issues. We've had breakfast in the hotel a couple of times, it's not bad (croissants were really nice), but expensive to eat there every day. We usually take stuff with us to have in the room, but otherwise you can go to Val d'Europe for a nice (and cheaper) breakfast.
We used to park in the street but recently they've made a lot of the streets near the hotel non parking (and we saw a few cars getting fined), so last time we payed to park in the hotel car park. Totally worth it and would do it again. If you're not driving, there's a shuttle, it didn't look as busy as the ones from the partner hotels, but we've never taken it so cannot really comment on it. If you want to walk, it's probably about 10 minutes to the Disney Village.
We've stayed there many times since getting our APs (usually a few trips every year) and will go back again
Oh, one thing, in the Hipark they don't come to clean the rooms daily (I think they come every 3 days on long stays). For us it was not a problem (and if you need it there's even a vacuum cleaner in the room), but I've had friends staying there and they didn't like that.