AlsoAsked is a People Also Ask (PAA) scraper and visualization tool and it does both those well. But there are some major differences between them and SearchResponse's PAA tool.

While People Also Ask questions are the base of both, fundamentally SearchResponse and AlsoAsked are very different tools and I'll start with a summary and then go in-depth into what makes one better over the other and what would be better for your use case.

Summary

AlsoAsked: a real-time scraper tool that scrapes PAA questions from Google for a given keyword search and uses the dynamic expansion of PAAs to pull in more questions and visualize the relationships between them.

Search Response's PAA Tool: a frequently updated database of 150M+ unique PAA questions which are collected from hundreds of millions of Google SERPs. The tool allows you to perform 'string' match searches across the entire dataset of PAA questions and get the results based on popularity.

This allows you to get a rich dataset as it's not just looking at a single SERP but hundreds of millions of SERPs.

Quick Comparison Table

1) Source of data

AlsoAsked: Google's SERP page for the given search query.

This is an important fact to keep in mind as your results could be different simply based on when you do the research.
In addition, AlsoAsked uses the dynamic expansion method to pull in more PAAs for a search query.

Example: Best Beginner Camera

Source: Nozzle.io

PAA questions for the same query, location and device can be different over time.

SearchResponse: Collects PAA questions from Google on a large scale and you can query this database to find PAA relevant to your topic. In addition, the 'Related PAA' function allows you to get even better relational data than what you see with AlsoAsked.

Example: Best Beginner Camera

Expanded result set using the Related PAA function for the PAA:
What is the best camera for a beginner?

2) Search Volume / Prioritization

AlsoAsked: only provides the PAA questions, it's up to the user to make a call on how to prioritize or guess the importance of each. PAA questions will generally have a 0 search volume in popular keyword tools.

SearchResponse: provides Popularity metric to help prioritize. This is derived by looking at the frequency of each PAA question across search queries and SERPs. If Google is showing the same PAA across multiple search queries, there is a good chance that you should be paying more attention to that PAA.

3) Topical Relevancy

AlsoAsked: uses the expansion method to generate a larger list of PAA questions, going more than 1 to 2 levels deep can lead to a massive drop in relevancy.

Example: alsoasked
(For this example, we used the query that Mark used  in his comparison video )

You can see by the 3rd layer, questions like 'Why is SEO important?', 'How do you find answers to questions?' etc. show up which are not relevant to the topic at hand.

SearchResponse: uses a string match which generally leads to highly relevant results.

In addition, SR has a 'Related PAA' function for each PAA question which uses Google provided relational data compiled across all the SERPs we have collected. This results in a much tighter and topically relevant result set.
Example: alsoasked

A single result comes up because we found only 1 PAA with a string match. But clicking the Related PAA button brings up more relevant questions:

You can compare the output of this to the 3rd level of the AlsoAsked result and see that you get a lot more useful competitor information & learn about 'Wordtracker', 'Keyworddit' etc. which is more relevant.

4) Competition Analysis

AlsoAsked: Doesn't offer any competitive analysis.

SearchResponse: Offers the ability to do competitive analysis in a variety of ways.
a) You can see what PAA slots a domain or URL is winning in Google SERPs and also get insights on what sort of sub-topics they cover.
Example: healthline.com

We have more than 3M unique PAA questions being answered by Healthline. On the left side you can see themes like 'hair', 'weight', 'eat', 'skin' etc. are some popular themes on Healthline.com

b) You can find the top winning domains dominating your topic.
Example: cat tree

5) Coverage

AlsoAsked: Coverage for your search query can be limited as Google only shows the PAA feature for around 60% of SERPs. This means certain queries will give you no result.

SearchResponse: Since you are searching the database most searches should provide results. This is also true because it captures PAA across hundreds of millions of SERPs so you should see a more comprehensive result set.

Using the Related PAA function, you can get a lot more related & important PAA questions like:
Can you baby proof a floor lamp?
What type of lighting is best for a nursery?
What is the best night light for nursery?
Etc.

6) Freshness

AlsoAsked: Since they do real-time scraping the data is as fresh as it gets. Google can introduce new PAAs related to current events in as soon as 24 hours. If you are a news publisher or write about trending events then freshness is of the utmost importance and AlsoAsked shines here.

SearchResponse: while the data is collected all the time from Google, the actual database that you query is around 2 to 3 months lagged. This is not an issue for most queries as long as the topic at hand is not time sensitive.

7) Language/Country

AlsoAsked: Has options for various languages and countries.

SearchResponse: US/English only.

8) Pricing

AlsoAsked: Prices start at $15/month for 100 searches. This roughly equates to approx 2,500 PAA questions.

SearchResponse: Prices start at $39/month for 200 searches. You can pull 40,000 PAA rows at this subscription level.

In addition, a subscription also gets you access to the very powerful People Also Search For and Related Searches tool. Using a combination of all these 3 tools, you have enough insights to create or enhance a content brief / complete article.

Conclusion

Currently there is no tool on the market that can provide you the levels of insights about your audience that SearchResponse can provide and this is because we take a large scale approach to data. The insights that you can gain from analyzing millions of SERPs is very different from what you can get from a handful of SERPs (which is what every other live scraping PAA tool does).

Use AlsoAsked if you want ideas and suggestions for real time or recent happenings as their data is live scraped. Their service also works for a variety of countries and languages.

Use SearchResponse if you are creating content for an english speaking audience and if your topics are not related to current or live events.

In addition, a subscription to SearchResponse also gets you access to the very powerful People Also Search For and Related Searches tool. Using a combination of all these 3 tools, you have enough insights to create or enhance a content brief / complete article.