A saying for something that's good but also has a downside

I'm trying to transition from a list of pros to a list of cons, and would like to have some sort of transition quote. Something in the form of,

"But, alas, (((something something quote quote)))"

Everything that has a beginning has an end, something along the lines of that.

Solution 1:

More context would make providing a more elegant transition easier. In the absence of that, here's a few general transitions that use the "But, alas," starting point.

• But, alas, that which glitters is not always gold.
• But, alas, every rose has its thorn.
• But, alas, nothing is ever free.
• But, alas, there are downsides [to this item being discussed].
• But, alas, [this item] is not perfect.

Solution 2:

In addition to Shaun's excellent suggestions, I like to turn the old adage on its head and say "every silver lining has a cloud."

You might also say "There is no light without darkness"; of course you could substitute two other related polar opposites that might be more appropriate for your subject matter. (warmth/cold, love/hate, etc.)

More prosaically, there's also "There's always a catch".

(Also, for his first suggestion, I prefer the phrasing "Not all that glitters is gold". :-) )

Solution 3:

You could call that "a mixed bag".

I used to think I had the perfect job, but as time went on I realized it was something of a mixed bag.

Solution 4:

There's a phrase "curate's egg" referring to a (mythical, surely) man of the cloth who, when asked by his host how his egg was, replied that it was "Good in parts".

It can be used directly as "But, alas, it's rather curate's egg", but you might prefer a more verbose option such as "But, alas, like the curate's egg it is good in parts".