which skills will I develop after 3 yrs in Equity research

You will get really good at powerpoint and visio, and ordering food.

I became good at finding investments but not hard banking skills, you really have to develop it on your own .

It depends on who you work for but some sellside guys are not into modeling and find it not important to driving revenues (trading commissions and banking deals) therefore their models are not complex and you may not learn much modeling. Of course you could work for an analyst obsessed with modeling and then you will be up to par with a banker who builds models all day. Also, some sellside guys love to travel with power point presentations, other sellside guys think its a waste of time and they will just bring the published research they want to talk about and then have all of the talking points in there head. The tough part of equity research is you are typically working one on one or two on one with a single analyst so you work the way he works, I went two years without out ever opening powerpoint, seriously, I didn't make one presentation the entire time. It didn't stop me from going to the buyside but if you asked me to make a powerpoint slide I couldnt do it to the level desired if for some reason I was asked to make one.

Answering the original post, of course buy side ER exists, hedge funds, mutual funds (Fidelity, Putnam, MFS, etc...). I am starting FT at a buy side shop this summer. From what I heard, on the sell side, you spend days to research on a company and write so much to produce 20 page report that might or might not have an impact at all, no one might even read it. On the buy side, you never write more than a 5 page report. In fact, the shorter the better because portfolio managers don't have time to read through all the fluff. Sometimes you present with scanned handwritten notes.....So it's a lot more about having good ideas, conveying them in an efficient manner, and making an impact. This is also the reason why a friend of mine declined ER FT offer from GS to go work as and ER associate for a mutual fund company.

Someone in the industry told me that it is better to start on sell-side equity research and then move to the the buy-side after a few years. He mainly talked about quality/structure of the training, network possibilities and reputation. In the end it all comes down to preferences.

there are more openings on the sell side for entry level i think

I did sellside then buyside and I have to say that most buyside shops are so small that if you start at one your network will be limited, especially the first couple of years. Over time you establish relationships with sellside guys who cover you and you meet people at conferences but those relationships aren't nearly as strong as the relationships you develop while working with people for a couple of years. Having said that, if anyone has the chance to go straight to the buyside then they should take it because its not as if after a two year banking program or ER the buyside is desperate to hire you. It's still an extremely difficult job to get so if you have the opportunity you should jump at it.

Sell-side is definitely easier to get into initially than the buy-side.