Well, things seem to have changed since this question was asked and a few comment are required:
InTech Open seems to have done a reasonable work until 2012, because a number of book chapters from that time had some impact and the webpage was not so misleading.
Currently, there are a number of doggy facts in the website:
A) They claim to be the "World’s largest Science, Technology & Medicine Open Access book publisher". This statement is hard to support because "largest" requires a metric and it is not clear what is their metric.
B) InTechOpen runs a number of Journals, but only two of them "INT J ADV ROBOT SYST" and Nanomaterials and Nanotechnology were indexed in SCR by Thomson-Reuters (currently by clarivate-analytics). Their impact index was below 1 and in 2016 both journals were acquired by SAGE journals. These continue to be published and their current impact index is still below 1.
C) The editorial has only 29 books adding up to 70 records in PuBMed BookShelf out of the 3391 books with 47305 chapters they register published on 13/april/2018, a miserable 0.86 % as books and 0.15% by chapter.
D) The advertise +57,400 citations in the Web of Science database and Even is the number is correct that amounts 1.2 citations per chapter. But because the verification of the data would take too long, I relied on their own sampling. Taking the data as given in their webpage, their most cited book chapters have:
-1004 citations in WofSci and 1584 in google scholar, for an average of 50.2 and 79.2, respectively. Taking this as representative sample of 20 out of 433 books allegedly referenced by the SCI, and using the same average we cannot justify more than 22000 citations. There is no data on individual chapters, so we cannot doble-check the calculation.
E) The current Book Processing Charge is 1200 € for such a low impact, sound too much. Frontiers, PLoS and BMC are just as expensive but their journals have and overwhelmingly higher impact and recognition.
Yes The produce the books, and these are online, but the price/quality ratio is too high!
In my view the editorial in gradually moving from a modest publisher with acceptable practices into a predatory publisher. It can make it to the Beall's list again sooner of later.
Intech open is a platform where you can find the solution and answer for your question related to every corner and aspects ..its a vast accumulation of knowledge sources..go ahead and explore knowledge
I received several invitations but did not respond. I always prefer to publish my work with a proper publisher such as Elsevier, Willey BlackWell, Springer, CRC, Francis and Taylor, Hodder and Arnold etc.