We just got back from a lovely week in Santorini staying at the Venus Beach hotel in Kamari on a half board basis. My partner and I went there for 1 week.
The Venus did sadly only give us a twin room as there were no doubles available, but other than that initial set back it was a pleasant stay. It is not a 4 star by English standards but is a nice place with a great swimming pool and a fantastic receptionist named Katerina.
The rooms are small and the bathrooms are tiny. Many people were complaining of the size of the bathrooms. I felt that it was adequate though and the maid service and cleaning was excellent.
The food we had for dinner was very nice - a wide variety of Greek cooking that is both tasty and homely. Breakfast was OK - the usual continental style of buffet breakfast that you could expect anywhere.
Kamari is a very relaxed resort but it is entirely touristy. I doubt any locals would go there to eat or shop and the prices can get a little cheeky.
The Venus is right near the black pebble beach. Be warned it is rather hot on the feet in the noon sun so bring thick flipflops or beach shoes!
The sea is beautifully clear and is lovely - I really recommend getting out of Kamari though and seeing the more interesting parts of the island such as Ia at the Northern tip, where you can enjoy fine dining and stunning views. There is also Imerovigli to see - it is one of the highest points on the island as is well worth a trip. There are various tours to the volcano, and to the one white sandy beach on the island by boat. All well worth doing. Santorini is full of history and culture...Acrotiri is closed at the moment but there is a museum in Fira with many Menoan artifacts - well worth a look.
I wish we had had more time to soak up all it has to offer. We will be going back there for sure but we will try to stay in Ia next time.
If you have kids and fancy a lively fun resort then Kamari is perfect. If you want romance and quiet it may be worth checking out the rest of the island.

My partner and I ages 25 & 27 have just came back from the venus, hotel was nice although our room was basic (found out from others some were better) pool area was very nice although people reserve sunbeds early so if you want one you have to be quick. food was ok a good selection for evening meal but was sometimes not hot enough. The staff were very nice and our rep was excellent as we had a problem the first day ( we had paid half board but the hotel thought we were b&b) this was resolved quickly with a complimentry lunch thrown in. All in all kamari is a lovely resort with many bars & restraunts although not very lively, don't worry about taking much evening wear as people don't seem to bother getting dressed up.we booked last minute with thomas cook and paid £670 for one week half board for two people. Talking to others in the hotel the prices seemed to vary and so did the standard of the rooms which we were'nt told upon booking. We had a lovely relaxing time in santorini but would'nt go back as its a bit quiet.

Hotel has fantastic beachfront/promenade location. We had a sea view room - these rooms are very small which is typical for Greece. The air conditioning and ceiling fan was fantastic and instantly cooled the room down. The shower was temperamental, sometimes you would get water, sometimes it would just be dripping! If you are used to these conditions in Greece then you will just accept it.
The hotel is clean and the pool is really nice.
Santorini itself is a small island, you can get from the top to bottom in 40 minutes. We hired a car for one day and managed to see everything we wanted to see. Beware, there are a lot of steep mountains/hills with no crash barriers so if you are scared of heights then I suggest you go on escorted trips. The beaches are all pebble and the sea gets deep quite quickly. The Aegean Sea can be quite rough most of the time.

We have just returned from the Venus hotel, the hotel is very basic but the staff are very helpfull. The bathrooms could do to be updated though we were ther for our daughters wedding so there were a few of us we had five diffferent rooms between us and none has a shower head that could be fixed to the wall we all had to hold them. The food wouldhave been great if it had been hot. The only bad draw back is that we all had our hair done buy hair and soul based in Oia they charged us 180 euros each we nearly died. So beware ask a price first we didnt and it cost us dearly.