A few months ago I had to escape from another Endurance International company -- FatCow.
Poor performance under moderate loads: 100-150 actives users does NOT mean that 150 users are accessing your site NOW, only that 100-150 users have accessed it in the last 15-30 minutes, and FatCow couldn't reliably serve pages at that rate during peak times. Users were getting lots of blank pages, and and there were many aborts on memory issues, apparently with XenTag. All of this finally went away when I moved sites to KnownHost.
Final straw was a thread about a perverted teacher that got busted after shagging two her students. 12K hits in two days apparently sunk their DB server, and they disabled that account, which included my most "lucrative" site ("lucrative" is a stretch, but it pays the internet bills) and several other XF sites & WP blogs.
In the course of moving ~9 (at the time) XF sites & 5 WP blogs across several accounts, I discovered that many of FatCow's DB backups were missing tables. In some cases NONE of the last three daily backups that they make available had complete tables. And their option to create DB backups in zip/gzip formats usually didn't work. Having to download a non-compressed 80MB backup to my laptop & then upload it to KnownHost is not fun.
Regarding their DB servers: Fatcow limits you to 75K requests per hour per user (raised from 50K when they first put the limit in place in ~2008). A busy forum can hit that limit without much effort.
And I had other issues with them over the years, like disabling MOD REWRITE without any notice, which kind left my 4 sites running vbSEO + vBulletin in limbo.
&c
Avoid them.