The Diono Radian 5 did poorly in Which testing when in forward facing mode. Diono released a statement saying that they tested it with the harness pads the wrong way around, which allowed the dummy to slip out of place. The pads are very long and have grippy sticky parts on them to help the straps stay in place.
It's not considered one of the easier seats to use - and personally I'm a little wary of this harness pad thing since it seems a very small error to cause such a big safety issue.
Boom Which don't look at aesthetics at all. This is an odd myth which floats around car seat groups. They are a consumer organisation and do look at several factors, but safety is rated the highest and ease of use second - because it's no use having the safest car seat in the world if you miss some crucial step in the instructions and render it unsafe!
But in any case, yes, rear facing is quite a bit safer simply because of the physics of it - the child is being caught by the whole shell of the seat and the energy of the crash dispersed into the shell, rather than being dispersed across the five point harness which puts strain on the child's body. It's less of an issue at 2 than it is at 1 (when it really is life or death) but ideally I would want to rear face until 3 really. Children in Sweden are mostly turned between their third and fourth birthdays, and the child passenger death statistics there are in single figures (and all catastrophic e.g. the whole car exploded).
OP, how heavy and/or tall is your DD?
If you like the Britax seats, I would really recommend the Britax Max Way Plus if you're looking for something to rear face up to 25kg (Again note that it scored low on Which - because they found it hard to install. It's the same install method as any other rear facing 25kg seat. For safety it scored very highly.)
Or the Britax Dualfix i-size is a great one if you're undecided about rear facing, it can be rear facing up to 18kg, but you can also forward face it and as forward facing seats go, it's a very safe one (top 5 on Which).
The seat covers/colours on this range (both Dualfix and Max Way Plus) are really nice as well. I especially like Burgundy Red which is quite purplish, but Fire Red, Moonlight Blue and the Cool Flow fabrics are lovely as well.
I do really like the Advansafix seat range, but I would recommend it for age 3+ personally. The seat itself is quite roomy at the base and I think a just-2 year old would rattle around in it a bit, as well as it being forward facing.
We have the Joie 360 Spin for my 23 month old (in Sea Deep) and I love it! That is another seat I would recommend.