Non regular flyer (around 2-3 times per year) from Birmingham, not flown in the past year though so I'll go on past experience.
Car parks are pretty good (if somewhat expensive) with a short walk to the terminals from the multi stories, and although I've never used it, the buses seem pretty regular from the long stay. I've arrived by rail once and it's very convenient, one stop from Birmingham New Street and a short 90 second trip on the skyrail and you're in the building. The drop off area has seen a bit of controversy with charging £1 for 20 mins but I don't have a problem with it, the area is right outside the front of terminal and is way better than queueing to get down that narrow road. Never arrived by bus or coach so can't comment.
The main check in area is bright and spacious, but the extension to it (think it's desk numbers 60+) is very narrow, which is fine for the likes of Lufthansa where people wander up, check in and then go, but when there's a holiday flight queueing it is very difficult to get past. The far end where Emirates use is ok as it widens again. The upstairs departure area is ok although I don't spend much time there. Security channels are better than before but can get very busy, I have queued down as far as Frankie & Bennies before, but that can be down to staffing levels rather than design.
Departure lounge is bright enough but it is with artificial light, the natural light has now gone since Dixons and Alpha expanded and took up the space by the windows overlooking the airfield. The shop layouts take up a large area and it can feel a little cramped at busy times.
Going to and from your aircraft can either be a pleasant experience or a nightmare depending on which pier you depart from. Pier A is quite simply awful, it's old, dull, dark and way too small for purpose. The waiting lounge for EK38 was way too small for an A330, I hate to think what boarding the 773 must be like. Good progress is being made though on the construction of it's replacement, I don't think anybody will be sad to see this go next year. Pier B is the total opposite, with a glass front that lets lots of natural light into the waiting areas, and it feels so much more spacious in comparison.
On arrival the Immigration area is bright and spacious, I've always passed through pretty quickly except once when the queue was up the stairs and halfway down the pier. The baggage reclaim is quite dull but guess it serves it's purpose, I always thought it was a little small at busy periods but I think they may have added an extra belt or 2 since I was last there.
Leaving the airport is fairly easy, a short ride to the railway station or a short walk to the car park. The road system is generally adequate but it can clog up when there's a large show finishing at the NEC, I think improvements are on the cards though.
Hope that helps.