I had a hard time finding a quick answer to this question, so I have knocked around the web, downloaded a bunch of hits that come up in the App Store when you search "Dialer" and tested few dialer/contact managers/speed dialers.
The first issue is that it appears that, unlike in the Android Ecosystem, there is no consistent naming convention. In Android, I used GoContacts and had read about DialerOne as a very strong alternative. GoContacts was fairly straightforward to use and gave me 4 pages of contacts (Favorites, Family, Local Friends, Long Distrance Friends) that I used religiously to dial. Sometimes, I voicedailed who I wanted, but sometimes I wanted to scan the list of friends for who I had been out of touch wtih for a while. GoContacts (for Android) did this perfectly:
(from GoContacts on PlayGoogle)
You can read more here:
On iPhone, I felt like I was in a relative Sahara of information. I found the Favorites list on the iPhone contacts anemic, and struggled with groups (I know how to do it, but so slow!).
After much investigation, I found a few apps that fit the bill, with the help of lifehacker once again, but interestingly, they did not mention the ones below (I don't think):
Lifehacker reviewed 4 products, one of which make my personal top 4 list of what i am currently using/piloting. My choices, in order of preference:
1. iGroup Contact (iTunes App Store, 4.7 stars as of 12/26/2012, $0.99 to create unlimited groups) - Wow. This app is over the top cool. Create and organize Groups on the "Groups" tab. It is super simple. Just drag the contacdt from the ALL tab to the tab of your choice. It works very smoothly. Plus, you can view "SmartGroups" - By Birthday, Place of Work, etc. It is completely great. The Favorites tab gives you 9 speed dial icons
(from the iTunes Store iGroup Contacts + Speed Dial page)
2. GODial Speed Dial with Facebook for iPhone (iTunes App Store, 5 stars as of 12/26/2012, free) - Fantastic app that lets you create multiple groups of speed dials with little effort. short touch on the icon, and it dials your preferred #. Long touch and you view the contact. (works very similarly to the best Android dialers). Looks as such:
(from GoDial app page in the iTunes store)
Works great for me!
3. FaceButtons Free - Great app and killer advantage is that it creates buttons right on your home screen (vs. in an app speed dial, which is what almost all other apps do).
4. Genius Dialer (usually $2, now $0.99) - Seems to work very similarly to #1 and #2 and gets good reviews.
NOTE: Without jailbreaking your phone, you CANNOT replace the default dialer on the iPhone. You can only access this via the icon. That is the advantage of FaceButtons Free above (#3) - it will put actual icons on your screen for speed dials.
Other programs that seemed to have significant issues/limitations for me:
X 5. Faces Visual Photo Dialer Lite (free) - This one works a lot like #1, but only 2 pages of contact speed dials are allowed, and it is a little less friendly in terms of dialing/options. I setup different icons for my wife's work/mobile (though after some futzing, I think this was overkill), and so on. But the two page limitation was frustrating, as I have four distinct pages of contacts I would like access to.
X 6. FaceDial Visual Dialer (free) - Much like Faces Visual Photo Dialer, this app can create shortcuts, etc. but I cannot figure out how to either speed dial OR open the contact... it only seems to speed dial (there is no way to "long click" to open the contact).
X 7. MyPhone+ for Facebook (free) - this is actually the most attractive, visually, but many reviews complain it duplicates your Facebook contacts (that would be bad).
X 8. Tacts (identified as the best choice by lifehacker) - does not work with iOS6/iPhone 5, apparently, so not an option for me :< Hope they can fix it and I can try it out. Seems to have similar features, benefits, and price ($0.99) compared to iGroup (see #1 above).
X 9. iSmart Dialer (again, identified by lifehacker) - Recent posts indicate bugs and some features missing (no recent call logs, deletes contacts).
X 10. Takephone Gold (identified by lifehacker) - Recent posts indicate that Takephone does not work well with recent iOS versions.
Do you have more info on any of these or do I have the "skinny" on one of them wrong? Please let me know... Trying to help iPhone users and those migrating from Android have a smoother transition!