This could encompass many things for an entrepreneur; investors, possible hires, sales leads, etc. I'd prefer a service that is a mainly mobile based.
What kind of contacts? I find out that the way to stay in contact is to create groups or communities around them.
Whatsapp: Family + Friends
Wechat + Line: international friends
I used contactually and it's good but its still a one-on-one that fades and doesn't feel natural. So I try to bring some people together (that I know have common interests) and that way I can jump in a have a conversation any time.
If you want to know about how this have work so far, give me a call and I will be happy to share my experiences.
I'm using Contactually as well and I agree that it could do with improvement. Have you had a look at RelateIQ, Pipedrive and Close.io . Close.io has a decent mobile app as far as I know and I believe you can get it to operate in much the same way as Contactually. In all honesty, I don't think anyone has solved this problem well enough and this market is ripe for the taking.
For mainly mobile based, take a look at Base CRM (getbase.com) and RelateIQ (relateiq.com). They both do a good job in helping you managing your contacts, leads, investors etc. while also automatically synchronizing all your email communications right into the CRM.
For non-mobile, check out close.io, which is the best inside sales tool on the market today (Primarily for sales teams selling over phone and email) and logs calls and emails automatically and cuts out data entry.