I understand what you mean. It depends, what you mean by better.
For german wines they are generally classified according to sweetness of the grapes upon harvest, starting from the least sweet: Kabinett, Spatlese, Auslese, Beerenauslese & Trockenbeerenauslese.
Keep in mind, this doesn’t necessarily mean that a Kabinett wine is not sweet at all, the grapes for kabinett are picked when they are ripe. As you go further, the grapes are left longer on the vine to ripen even more and hence develop more sugars. As you go into Beerenauslese and Trockenbeerenauslese, these are intensely sweet because Noble Rot has been occurred. It is a fungus which causes the grapes to shrivel as the water content is leached out leaving a higher concentration of sugars in the grapes, hence it is a very sweet wine.
In terms of pricing, Kabinetts are generally the most affordable and as you go sweeter and sweeter, it gets more and more expensive. This doesn’t mean that Kabinetts are lousy and that we should all drink only sweet wines since they are ‘better’. One of the causes for higher prices for sweeter wines is due to the large amount of manpower required to harvest them and the generally smaller yields because the longer you leave on the vine, the more you risk it being damaged as it gets colder and colder, plus other risks include Grey Rot, which will render the grape un-useable.
Due to the low yields, supply is low and popularity for sweet wines are always high, so if you know your economics, the price is gonna turn out high. Lastly, these expensive late harvest dessert wines tend to age very well (look at Sauternes), after the initial years of youthful fruit, a good dessert Riesling will develop complex layers of flavours and textures that will make any wine connoisseur go weak in the knees.
So that’s a lot of write-up, just to give you some context of sweet or not sweet. As to your question whether it’s better or not, it’s hard to compare unless I know what the wines are and their individual price points. Comparing a Kabinett with an Auslese is like comparing apples and oranges, they are made differently and in a different style for a different purpose. One will definitely be sweeter than the other, but one can be more well made than the other.
What you need to look out for when drinking sweeter wines to see if it’s well made, is the notion of balance. Everyone likes sugar and something sweet, girl chug sweet wines like no one’s business and boys like it too, but they’re too shy to admit it

. But while sweet fruit is always nice, the discerning wine drinker that not all sweet wines are made equal, one of the most basic elements of a well-made dessert wine is Acidity.
Without acidity, you will get a fat flabby but sweet wine that doesn’t have character (just sugar) and won’t age well. Next time make a cordial drink by mixing orange concentrate and water and give a good squeeze of lemon, the taste is more refreshing and focused compared to just concentrate and water. Then comes the complexity of flavor. Does the wine lend more flavours to your taste buds and nose? Are the flavours coming together nicely or is it all disjointed and all over the place?
I think maybe the one your friend brought was ‘Blue Nun’? I dunno. Next time we meet up we can do a Riesling thing also, just to see the differences.