I think for rear-facing, when the seat is correctly installed, they should have the same recline. My boys were both too tall for their bucket seats well before they hit 1 year, so we had no choice but to move to convertible seats (we used a Britax Roundabout as a rear-facing convertible seat).

They are recommending we keep our little ones rear-facing as long as possible and at least 2 now (based on the seat height/weight restrictions). http://aapnews.aappublications.org/cgi/content/full/30/4/12-a

My DD #3 wasn't 20 lbs until about 20 months but we started using the convertible seat with her around 10 months. If you like being able to carry her in "the bucket" then the convertible seat is a pain to get used to. If you always leave the bucket in the car it won't be much different. You also might want to check length limits on your infant seat because most kids outgrow them length wise long before they outgrow them for weight.

My last DD is 2 1/2 and is actually still rear facing even though she's now up to 25 lbs (finally). RF is safer & she can see & talk to her sisters in the last row - LOL!

We only used the infant car seat for 9 months, then moved to a convertible. It seems so much more comfortable for him, plus the one we got has cupholders. We bought the Graco MyRide 65. I found it cheapest at Target. It is not as convenient for getting in and out of the car, but I think he likes it better.
BTW, there are toys that clip on to the convertible car seats. I wondered about that since all the toys I had were straps that went on the handle of the infant carrier. Try Tiny Love Sunny Stroll Arch.

My DS was in his infant carrier until he was about 15 months old and then in a rear facing convertible car seat until he was a few months past his second birthday. We moved him into the convertible car seat when he got too long for the infant carrier.