I have not spent that much time so far in Kibana4 against the same data we use Kibana3 for. One of the first pain points I found was the need to go from Discover to Visualization to Dashboard for every little thing you want to add to a Dashboard. It is better now that you can skip the Discover part. Another is you can't seem to assign colors to a query like in Kibana3. For example I have a dashboard for IIS logs, I have 4x queries that search give me data for each host producing the data, they are all blue tinted. Then I have another 4x queries that get response times, 0-999,1000-1999,2000-3999 and 4000-1000000, they are tinted green,yellowgreenish,yellow and red. Then I have a few histograms that use either only the host queries or only the response time queries. The host queries are mostly informational but the response time ones are there to grab your attention.
I have mostly used Kibana4 with some earthquake data, totally different use case but I definitely can see that Kibana4 shines when exploring data.
I created an issue here, https://github.com/elastic/kibana/issues/4060 for one of the problems I found regarding tables.