I know that there are lots of info on these two model in this forum already. But I have not yet seen the info I am about to address in this forum. So I hope it is ok still to post

I have tried PX320 a few weeks ago. I like it very much but I decided to buy PX330 since it is a upgrade version of PX320. However, at the moment I am hesitating. I read a review in youtube and in other website. Most comment on PX330 are very positive. However, there are a few things to concern about this unit.

Here is from what I read. Although PX330 is a upgrade version of PX320, there are also down side as following.

1.The speaker in PX320 is actually better because they separate high frq and mid/low frq, while the one in PX330 has no separation.

2. PX330's body is made of cheap plastic and this might be an issue later on. (I couldn't remember what PX320's body made of)

I would like to buy a DP and use it (for practicing and small gigs) for at least 3 years.
I concern less about the speaker issue. But I do more on the plastic issue.
Although PX330 is better in terms of key action and patches organization (since it has bigger screen), I would want to choose the instrument that is solid enough to last long. Also I am planing to the instrument online and have it shipped to my country. It has to travel a long long way (to Switzerland).

Do you think the plastic issue will be a problem?
Or are there any other model from other brands that is in this price range and can compete with these two?

Unless you live in China, everyone has to have their keyboards shipped. I don't think Casio changed the kind of plastic used. But you can get a good hint about sturdiness by looking iat the weight in the specs.

You are going to need a hard case, with wheels. The Casio DPs are not sturdy enough to move without a case.

All of Casio's stage piano's are made of plastic including the PX-320. It seems that Casio has decided that musicians who gig are underserved and have designed their pianos smaller and lighter in weight. This started with the PX 120/320 and has carried over to the PX130/330. I figure Casio is betting this segment of the market will upgrade in 3-5 years so I would say this is the average life span of their product line. If you are going to do gigs get a good hard case.