What are the major differences between the two above breeds? Are temperaments similar?

Is the Bolognese a breed? I understood it was a crossbreed ...

It seems it is
Bolognese Breed Standard

sorry meant to say seems it is a breed

Yes, definitely a breed. Not sure about the differences though - possibly the bichon needs more coat care? There should be something about temperament in both breed standards on the KC site. :-)

Oooh now that is what I like about C D ..you live and learn :)

I think the Bichon, Bolognese, Coton & Havanese all have similar looks but it's all up to the difference in coat preparation & some allow markings.

Actually I think the Bolognese' coat is harder to look after.  The coat has to be left curlyish, Bichon can be properly brushed and trimmed into the said shape.

I like both breeds although the Bichon seems a bit more outgoing.  Think prices between the four breeds mentioned by ChristineW is the big difference.  Bichon's being the cheapest and the Coton's being extremely expensive!!  Liz Stannard is the person in the know re. the Bolognese and she's easily approachable. I can't think of her kennel name but if you put her details in a search you'll find her, Kath Biggins I think her name is is good friends with Liz and they both live in the Cheshire area.  I think the kennel name is Shiarita or something like that :d

Cathy Begg's details are on this site under Bolognese kennel name Clarchien

I have a book aimed at helping people pick the breed they want. Here's what they say
Bichon
Are good natured dogs which make excellent pets. Lively and vivacious, they are friendly with everyone and the make easy, delightful companions. A friendly dog that enjoys human company. Potential problem is may be hard to housetrain.

Bolognese
Similar to the Bichon but more serious, shy and reserved with strangers. Bolognese like to form strong bonds with their owners with whom they are affectionate and devoted. Potential problems are they may suffer from seperation anxiety and may be hard to housetrain.

The rest of the text basically says the Bichons are a little more outgoing than the Bolognese. It can't replace talking to people who really own the breeds but it may be a start for you.

There is a Bichon living near us which is extremely friendly and very active - gives my manic Welsh Springer a run for her money! Her housetraining took a little longer than her owner would have liked but she got there in the end.

I have a Bichon and he is a brilliant little dog - well actually he isn't so little he weighs about 12 kg. He is great with kids, friendly, as active as you want him to be - can't fault him really.  His housetraining did take quite a long time - he was 8 months before he was fully housetrained but he is fantastic now and never does anything inside and always goes to the back door to go out even when its pouring with rain. :-)